“We cannot live without the Lord’s Supper,” cried the Christians of Abitina in the time of Diocletian.  For them it was life or death.  Threatened with execution, they declared, “Without fear of any kind we have celebrated the Lord’s Supper, because it cannot be missed; that is our law.”  The testimony of these fourth-century martyrs to the critical importance of the Sunday Eucharist could not be more vivid.

Even today some Christians put their lives at risk by daring to take part in Sunday Mass.  In a sense Sunday Mass is a matter of life or death for every follower of Jesus.  Without the coming together of the church, without the nourishment and inspiration the Eucharist gives, faith can wither and die.  By contrast, when believers gather to celebrate the Lord’s Supper, faith is brought to life and the work of redemption carried on.

The terms “Sunday” and “Eucharist” each carry a wealth of meaning that enriches the other.  In biblical tradition Sunday is the first day, the day of creation, the day of light.  For Christian believers it is the day of the Lord, the day of resurrection, the day of new creation, and the day of the Church.  
 
The Eucharist is what Christians do in obedience to Jesus’ command at the Last Supper: “Do this in memory of me.”  They meet together, share the good news, give thanks and praise, receive the holy gifts, and go forth.  In so doing they celebrate and enter into the saving mystery of Jesus’ death and resurrection.  
 
“Sunday” and “Eucharist” thus combine to create the action we call Sunday Mass.  While Mass is regularly celebrated on weekdays, Sunday Mass has a unique importance in the life of the Church.  
Down through the centuries the meal celebrated in the Lord’s memory has attracted a variety of names.  It has been called the Lord’s Supper, the Eucharist, the sacrifice of the Mass, Holy Communion, or simply Mass (see the Catechism of the Catholic Church # 1328-1332 for a fuller list).  Here the two most familiar terms, “Eucharist” and “Mass,” are used interchangeably.  The word “Eucharist” itself has a dual reference.  It can mean either the action of the Mass or the Body and Blood of Christ that we receive in Holy Communion.
 
The Bishops of the Second Vatican Council called the Mass the “fount and apex of the Christian life” (Dogmatic Constitution on the Church, 21 November 1964, #11).  Because they understood the supreme importance of the Eucharist, they encouraged everyone to participate as fully as possible.  
 
This is how they put it in the Constitution on the Sacred Liturgy (4th December 1963, #14): Mother Church earnestly desires that all the faithful should be led to that fully conscious and active participation in liturgical celebrations which is demanded by the very nature of the liturgy.  Such participation by the Christian people as a “chosen race, a royal priesthood, a holy nation, a redeemed people” (1 Peter 2:9) is their right and duty by reason of their baptism.
 
This explanation of what happens at Sunday Mass is offered in service of the goal of full, conscious and active participation. First we’ll go step by step through the various parts of the Mass.  Along the way we shall locate Sunday Mass in the context of the annual cycle of the church’s prayer, the liturgical year.  We will finish by returning to the subject of full participation.  From time to time reference will be made to the official church document that spells out how the Mass should be celebrated.  It is called the General Instruction of the Roman Missal, abbreviated to GIRM.
 
THE SHAPE OF THE MASS
The action of the Mass takes place in four phases.  In the first – the Introductory Rites – we gather together and ready ourselves for all that is to follow.  This paves the way for the next two parts that form the substance of the celebration.  In the first of these – the Liturgy of the Word – we listen and respond to the word of God.  Next, in the Liturgy of the Eucharist, we present the gifts, give thanks over them and receive them back in Communion.  The fourth and final part – the Concluding Rites – serves to bring the celebration to a close and send us forth.
It is helpful to keep this simple overall schema – gathering, hearing, thanking and eating, then going forth – in mind because each of the four parts has further subdivisions that could result in our losing sight of the whole.  Here is a more detailed but still somewhat simplified outline of the whole celebration:
Introductory rites
• Entrance
• Sign of the cross and greeting
• Introductory remarks
• Penitential act 
• (Hymn of praise or “Gloria”)
• Collect
 
LITURGY OF THE WORD
• First reading
• Responsorial psalm
• Second reading
• Gospel acclamation
• Gospel reading
• Homily
• Profession of faith
• Universal prayer
 
LITURGY OF THE EUCHARIST
• Preparation of gifts
o Preparation of altar
o Collection
o Procession of gifts
o Prayer over the offerings
• Eucharistic Prayer
• Communion rite
o Lord’s Prayer
o Sign of Peace
o Fraction rite
o Communion
o Prayer after Communion
 
Concluding rites
• (Announcements)
• Greeting and blessing
• Dismissal
 
Introductory rites
It is hard to pinpoint the moment Mass begins.  Is it when parishioners leave home and set out for Mass?  Is it when they are welcomed as they enter the church?  Is it when everyone has taken up their place in the church?  All these moments play their part in preparing for the celebration but the Mass proper begins with the entrance of the priest celebrant and other ministers, generally while the assembly sings a suitable hymn.
After the priest has reverenced the altar with a kiss (the altar being a symbol of Christ at the centre of the church), he makes the sign of the cross and greets everyone with one of the given formulae.
He may then say a few words to introduce the celebration of the day, before inviting everyone to acknowledge that they are sinners to whom God offers forgiveness.  There are several forms of this penitential act, all brief.  Part of it may be sung.  This act of penitence makes it clear that only the mercy of God makes our prayer together possible.  
Except during the seasons of Lent and Advent, the whole congregation then recites or sings the hymn of praise, “Glory to God in the highest,” otherwise known simply as the Gloria.
The final element of the introductory rites is the Collect.  The priest calls us to pray in silence before “collecting” our prayer and voicing it aloud to God in our name.
While there are several different parts to the introductory rites they form a unit that has a single purpose: “to ensure that the faithful . . . establish communion and dispose themselves properly to listen to the Word of God and to celebrate the Eucharist worthily” (GIRM #46).  In other words, they gather everyone together as one and prepare them for all that is to follow.
 
THE LITURGY OF THE WORD
Apart from the opening and closing rites, the Mass consists of two major parts, the Liturgy of the Word and the Liturgy of the Eucharist.  These are not separate and unrelated, but “so closely interconnected that they form but one single act of worship.  For in the Mass is spread the table both of God’s Word and of the Body of Christ, and from it the faithful are to be instructed and refreshed” (GIRM #28).  All the same, the focus in each part is distinct.  In the first it is on the table from which the word of God is proclaimed, the ambo.  In the second it is on the table from which we are fed with the Body and Blood of Christ, often simply called the altar.
One of the great achievements of the Second Vatican Council was to ensure that Catholic believers were fed a much richer diet of the word of God, especially at Sunday Mass.  After the Council a large team of international biblical and liturgical scholars worked together to produce a book of scripture readings for Mass.  It is called a Lectionary.  It does not by any means contain the whole Bible but it does have a wide range of readings from both the Old and the New Testament.  The Sunday readings are arranged in a three-year cycle, with each year’s selection being ordered to the seasons and feasts of the Church’s year.
 
The Liturgical Year
Before describing how the readings are organised on any given Sunday, it will be helpful to get the church’s year of worship – the Liturgical Year – in focus.  At the heart of the year is the three-day memorial of Jesus’ death and resurrection called the Paschal Triduum.  It begins with the celebration of the Lord’s Supper on Holy Thursday evening, continues with the Commemoration of the Lord’s Passion on Good Friday afternoon, comes to a climax with the Easter Vigil on Holy Saturday night, and concludes with Evening Prayer on Easter Sunday.  
This intense series of celebrations ushers in the fifty-day season of Easter.  From Easter Sunday to Pentecost Sunday the church revels in the Spirit of the Risen Lord.  Just as the church takes time to immerse itself in the mystery of the resurrection, so it takes time to prepare for the Triduum.  It does this by observing a forty-day season of repentance and renewal called Lent.  This starts on Ash Wednesday and concludes on the morning of Holy Thursday.
The other two seasons are centred on the birth of Jesus.  The first is the four-week season of Advent.  This is a time of hope and promise that looks first to the final coming of Christ and then to his birth in human history.  The celebration of Jesus’ nativity is not confined to Christmas Day.  The season of Christmas continues beyond New Year’s Day and concludes with the feasts of Epiphany and the Baptism of the Lord.
Together these seasons make up about five months of the year.  The remaining seven months are divided into the two parts of what is called rather misleadingly Ordinary Time.  Week by week through this season the church follows the path of Jesus’ public ministry – no ordinary journey.  In one year (Year A) we read from the gospel of Matthew, in the second (Year B) from the Gospel of Mark, and in the third (Year C) from the Gospel of Luke (the Gospel of John is read every year from late Lent to the end of the Easter season).
Thus in chronological order from the beginning of December to the end of November we have:
• Advent
• Christmas
• Ordinary Time Part I (anywhere from 5 to 9 weeks)
• Lent
• The Paschal Triduum
• Easter
• Ordinary Time Part II (from about 24 to 27 weeks). 
Punctuating these seasons are special feast days of Jesus, Mary and the Saints.  Sometimes these are so important that if they fall on a Sunday they take over from the normal Sunday observance.
The Sunday readings
There’s more to the Liturgy of the Word than the readings but they form the bedrock.  This is how they unfold:
• First Reading
o Responsorial Psalm
• Second Reading
o Gospel Acclamation
• Gospel.
All the readings are proclaimed by designated members of the congregation, except for the Gospel which is reserved to the priest or deacon.  
The First Reading is always taken from the Old Testament, except during the Easter season, when it comes from the Acts of the Apostles.   Most of the time the first reading is chosen because it has a connection of some kind with the Gospel of the day.  
After a period of silence (not often observed), the Responsorial Psalm is sung or proclaimed.  It usually consists of three or four verses of a psalm that echo the theme of the first reading.  First a one or two-line response is announced or sung, then repeated immediately by the whole congregation and after each verse.  The aim of the Responsorial Psalm is to enable everyone to take the Word of God to heart.
The Second Reading comes from the writings of the New Testament other than the Gospel.  Most often it is an excerpt from one of the letters of Paul, but it could also could from the letters of Peter, James or John, or another writing such as the Book of Revelation.  During Ordinary Time these readings follow on from one another Sunday by Sunday, but are independent from the First Reading and Gospel.  A period of silence should follow.
The Gospel Acclamation is a short burst of praise that prepares for the gospel reading.  Except during Lent it is called the Alleluia verse.  It is always meant to be sung.
The Gospel Reading is the cornerstone of the Liturgy of the Word.  Its importance is reflected in the honour given to the gospel book and in entrusting its proclamation to the priest or deacon.
Each of the four seasons – Advent, Christmas, Lent and Easter – has its own set of rules as to how the readings have been selected and are inter-related but the above account will have to suffice for now.
Completing the Liturgy of the Word
Once the readings have been proclaimed, the priest or deacon has the privilege and task of “breaking open the word” in the homily.  The role of the homilist is to assist the congregation to experience the word of God as “living and active” (Hebrews 4:12), so that their hearts will burn within them as happened for the disciples at Emmaus (Luke 24:32).  In this way, as Pope Francis wrote in his encyclical The Joy of the Gospel, “the homily can actually be an intense and happy experience of the Spirit, a consoling encounter with God’s word, a constant source of renewal and growth” (#135).  This experience would be enhanced when the homily is followed by a period of silent reflection.
After that comes the Profession of Faith.  All stand to recite together one of the ancient formulas that sum up the essential beliefs of Christian believers.  The Apostles Creed is the older and shorter form; the Nicene Creed is a fuller version forged in the doctrinal controversies of the early ecumenical councils.
The final element of the Liturgy of the Word is the Universal Prayer, also called the General Intercessions or the Prayer of the Faithful.  The priest opens and closes the Prayer, but the petitions themselves (usually numbering about half a dozen) are led by one of the faithful.  They address the present needs of the church and the world in the light of the day’s Word of God.  Each petition finishes with an invitation to all to join in a response. 
 
LITURGY OF THE EUCHARIST
As the Mass progresses, the focus shifts from the table of the Word to the table of Eucharist.  The Liturgy of the Eucharist falls into three parts.  The first is a preparatory phase called the Preparation of Gifts; the second is the solemn prayer of praise and petition over the gifts of bread and wine called the Eucharistic Prayer; and the third is the Communion Rite during which the faithful are fed with the Body and Blood of Christ.  Each of these is built up out of smaller units.
 
Preparation of Gifts
While the altar table is prepared with cloths and vessels and missal, a collection is taken up.  This gives everyone the opportunity to make an offering “for the poor or for the Church” (GIRM #73). Asking for financial support is not at all a recent practice; its origins can be traced back to Paul the apostle’s appeal to the Corinthians and others to support the struggling community in Jerusalem (see 2 Corinthians 8-9).  It was rooted in his powerful sense of unity between the churches and his theology of the Body of Christ.
Once the monetary collection is complete, the gifts of bread and wine are brought forward in procession through the body of the church to be handed over to the priest.  The bread should “truly have the appearance of bread” and should be large enough for the priest “to break it into parts and distribute these to at least some of the faithful”; the wine “must be from the fruit of the vine” (GIRM # 321).  
When the collection is brought forward at the same time as the bread and wine, a link is made between these two forms of gift.  Both express self-giving in the spirit of Jesus Christ who became poor for our sake that we might become rich in him (2 Corinthians 8:9).
The priest prays a short prayer of blessing over the bread and over the wine, then washes his hands in a symbolic gesture, before inviting the whole assembly to be united with him in prayer.  The final element in this unit is called the Prayer Over the Offerings.
 
Eucharistic Prayer
The centrepiece of Sunday Mass is the Eucharistic Prayer.  This is an extended solemn prayer offered by the priest in the name of the whole congregation.  It begins with a short dialogue between the priest and people.  This exchange allows the assembly to voice its approval, as it were, for the priest to be “the tongue of the body.”  
The primary form of the people’s participation is attentive listening, but the prayer is punctuated by three moments of active involvement.  At the end of the first part of the prayer (the Preface), everyone sings or recites the acclamation Holy, holy, holy Lord, God of hosts, often called the Sanctus.  Further on, after the priest has proclaimed the Institution Narrative, he announces “The mystery of faith.”  In response the congregation either says or sings one of three Memorial Acclamations.  The very last word belongs to the whole assembly.  Once the priest prays the concluding section of the prayer, the Doxology, everyone gives their assent with the Great Amen.
The Eucharistic Prayer may seem rather complex but its underlying structure is simple.  It begins as a prayer of thankful remembrance and then becomes a prayer of confident petition.  First the church gives thanks for God’s work of creation and salvation.  The highlight of this grateful remembering is the action of Jesus at the Last Supper.   Just as he took bread and wine and gave them to his disciples as his Body and Blood, so the church obeys his command to do so in his memory.  It asks God to send the Holy Spirit to consecrate the gifts of bread and wine and to make the church “one body, one spirit, in Christ.”  It goes on to intercede for both the living and dead before concluding with a burst of praise and the people’s Amen.
There are ten authorised Eucharistic Prayers.  The first four are simply known by their number, eg Eucharistic Prayer II.  Eucharistic Prayer I is also known as the Roman Canon.  In addition there are two Eucharistic Prayers on the theme of reconciliation, three for use with young children, and one for “Use in Masses for Various Needs” that comes in four distinct versions.
Most of these Eucharistic Prayers begin with their own fixed Preface, but for Eucharistic Prayers I-III a choice may be made from a wide range of Prefaces, each of which has its own character.
 
Communion Rite
Sunday Mass comes to a climax with the Communion rite.  The Word of God has been proclaimed, the gifts of bread and wine have been consecrated, and now the faithful are invited to Holy Communion to become one with Christ and with one another.  This part of the Mass proceeds through a series of steps.
To prepare for Holy Communion everyone stands to pray together the prayer Jesus taught his disciples, the Lord’s Prayer.  This is followed by a prayer for peace and an invitation to offer a Sign of Peace to those nearby.  This is much more than a friendly social gesture; it is a profound expression of fraternal love.  It readies everyone for Holy Communion by affirming unity among the members of the Body of Christ.
The unity of the church is also signified when a single bread has been consecrated for all to share.  The one bread is broken so that all can receive one part and become one body in Christ (GIRM # 321).  One of the earliest names for the Eucharist was in fact “the breaking of bread.”  This moment in the celebration is called the Fraction Rite.  As this takes place, and the chalices are prepared, everyone recites or sings the litany known as the Lamb of God or Agnus Dei.
After the priest has shown the holy gifts to the assembly and invited them to pray, he and the Ministers of Holy Communion take up their stations.  The faithful process forward to receive the Body, then the Blood, of Christ.  The normal manner of receiving the Body of Christ is to stand and be given the host in uplifted open hands for transfer to the mouth.  To receive the Blood of Christ the communicant is given the chalice by the minister, takes a sip, and hands it back.  For reasons of hygiene, the minister will wipe the rim of the chalice and turn it for the next communicant.  The Body of Christ is given to be eaten, and the Blood of Christ to be drunk, hence the practice of intinction (ie the communicant dipping the host into the consecrated wine) is officially discouraged.
A processional song may be sung to accompany the distribution of Holy Communion.  All are encouraged to observe a period of silence after Communion.  This may be followed by a song of thanksgiving.  The Communion rite concludes with the Prayer after Communion offered by the priest.
 
Concluding rites
Before blessing the assembly and sending them forth, the priest or parish representative may first draw everyone’s attention to forthcoming events and activities.  These announcements should be brief.
The Mass draws quickly to a close with the priest’s greeting and prayer for God’s blessing on all.  Then he, or the deacon if there is one, sends everyone forth to live what they have celebrated.
Full, conscious and active participation
The full, conscious and active participation hoped for by the bishops of Vatican II is one that engages Mass-goers in body, mind and spirit.  While there are many ways that people participate in the Mass physically (by their posture, gestures and movement) and vocally (by joining in all the sung or spoken parts), these are secondary unless they promote interior participation.  Full participation comes about when people pray with all their heart and soul and mind and strength (cf Mk 12:30).  The role of all the words and symbols and ritual action of the Mass is to engage the whole person at a deep level of faith.
Attentive and receptive listening plays a key role in all this.  Listening with an open mind and heart is not a passive act; it is a chosen attitude.  Sunday Mass offers a wealth of opportunities to practise this kind of listening.  The Scripture Readings and the Eucharistic Prayer call for sustained attention; listening receptively to other elements, such as meditative music, may bear much fruit too.
Several times reference has been made to occasions of silence in the Mass.  These are of the utmost importance.  They allow Mass-goers to absorb what has been said and done and to let it bear fruit in their hearts.  Times of silence are not empty but full of promise.
Equally numerous have been references to singing.  Music has an invaluable role to play in the celebration of Sunday Mass.  As the General Instruction says, “Singing is the sign of the heart’s joy.  Thus St Augustine says rightly, ‘Singing is for one who loves,’ and there is also an ancient proverb: ‘Whoever sings well prays twice over’” (GIRM #39).  In choosing what will be sung, the highest priority should be given to singing the dialogues and acclamations of the Mass, followed by the responsorial psalm and processional chants for the Entrance and Communion.  This ensures that the parish community sings the Mass rather than sings at Mass.  There’s a world of difference between the two.
 
Ministries
The Vatican II Constitution on the Sacred Liturgy established clear principles for specific forms of active participation.  These are called liturgical ministries.  There are diverse roles to be filled, reflecting the nature of the liturgy and the gifts given to the local community.  
The Mass is not a ceremony performed by the priest in front of a passive audience.  Rather the priest presides over and coordinates a whole range of ministries.  Thus, “Servers, lectors, commentators, and members of the choir also exercise a genuine liturgical function” (GIRM #29).  In fact, no-one should serve in multiple roles.  “In liturgical celebrations each person, minister or layman, who has an office to perform, should do all of, but only, those parts which pertain to his office . . .” (GIRM #28).
 
Conclusion
It is fitting to close this exploration of the liturgy of Sunday Mass with an excerpt from #45 of Pope John Paul II’s Apostolic Letter on the subject of the Lord’s Day (Dies Domini, 31 May 1998).  He makes the point that Mass does not end with the dismissal: “For the faithful who have understood the meaning of what they have done, the Eucharistic celebration does not stop at the church door. . . Once the assembly disperses, Christ’s disciples return to their everyday surroundings with the commitment to make their whole life a gift, a spiritual sacrifice pleasing to God (cf Romans 12:1).”
 

- Authorised by Dr Paul Taylor, Executive Secretary of the National Liturgical Council.

References

 
GLOSSARY
 
Ambo
The ambo is the reading stand or ‘table of the Word’ from which the Scriptures are proclaimed during the Liturgy of the Word.  Its size and design distinguish it from a mere lectern.
 
Confirmation
Confirmation is a sacrament of initiation.  The child or adult being confirmed is anointed with consecrated oil (chrism) conveying the gift of the Holy Spirit.  Together with baptism and eucharist, confirmation orients the candidate towards full participation in the life of the church.  Normally it is administered by the bishop and is never repeated.  
 
Covenant
Covenant is a biblical term signifying the bond between God and humanity.  God’s pledge of faithful love for all that has been made calls us into a relationship with God that the prophets likened to a marriage.  
 
Deacon
A deacon is a person ordained to assist bishops and priests in the ministry of word and sacrament. Deacons may be either permanent or transitional (on the way to priesthood); permanent deacons may be married.  At Mass, deacons proclaim the gospel, pray the general intercessions and assist with the chalice. They may also baptize and officiate at weddings.
 
Doxology
A doxology is a hymn of praise to God, such as the Gloria, or a short concluding expression of praise such as the Glory be or the words that bring the Eucharistic Prayer to a close: “Through him, with him, in him … Amen.”
 
Eucharist
“Eucharist” comes from a Greek word meaning thanksgiving.  It can refer to one or more of several interconnected things: the complete celebration of Mass, the Body of Christ received in Holy Communion, or the whole role of the sacrament in the life of the Church.
 
Eucharistic Prayer
The Eucharistic Prayer is the solemn prayer of thanksgiving and intercession at the heart of the Mass.  It is prayed aloud by the priest in the name of the whole congregation who join in by acclamations and attentive listening.  As the priest prays, invoking the Holy Spirit and speaking the words of Christ, the bread and wine become for us the Body and Blood of Christ.
 
Homily
The homily is a form of preaching given by a bishop, presbyter or deacon within the Liturgy of the Word.  What distinguishes the homily from a sermon is that it draws on the Scripture of the day or a liturgical text and applies it to the lives of those taking part.
 
Institution Narrative
The Institution Narrative is that central part of the Eucharistic Prayer in which the priest recalls the words and actions of Jesus at the Last Supper.  The words used are a combination of those found in the gospels of Matthew, Mark and Luke and in the writing of St Paul.  It is also known as the Supper Narrative.
 
Invocation of the Holy Spirit
During the Eucharistic Prayer the priest twice asks God for the work of the Holy Spirit, first to transform the bread and wine into the Body and Blood of Christ, and then to draw those present into union with one another and with Christ as his Body.  The proper name for this invocation is epiclesis.
 
Lectionary
The lectionary is a large book containing the passages selected from the Old and New Testaments for reading out at Mass.  These texts are arranged according to the cycle of seasons that make up the church’s year of worship.  There are three annual sets of Sunday readings (A, B, C) and two for weekday readings (I, II) as well as readings for other rites such as marriages, funerals, and religious professions.
 
Lector
A lector is a person who has been formally instituted in the ministry of proclaiming the Scripture readings at liturgical celebrations.  A person who proclaims the Scriptures without being so instituted is called a reader.  The gospel reading is reserved to the priest or deacon.
 
Liturgical ministries
Liturgical ministries are the specific roles played by select members of the congregation during the celebration of Mass and other liturgies.  There is a wide range of such ministries, the most common being proclaiming the scriptures, helping with the distribution of Holy Communion, assisting at the altar, and supporting the singing.
 
Liturgical year
The liturgical year is the annual cycle of seasons and feasts that celebrate and make present the entire mystery of Christ. It begins with the First Sunday of Advent and concludes on the Saturday after the feast of Christ the King. The liturgical seasons are Advent, Christmas, Lent, Easter and Ordinary Time, with the Paschal Triduum serving as the centrepiece of the whole year.  
 
Liturgy
Liturgy is the term used to refer to the official public worship of the church.  Originally meaning “the work of the people,” it includes the seven rites of the church called sacraments, among which the Eucharist is central, and other rites such as the Liturgy of the Hours, blessings, and funerals.
 
Lord’s Supper
The Lord’s Supper is another term for the celebration of Eucharist.  It draws attention to the fact that the Eucharist is in the form of a meal, and that meal is with the risen Lord.
 
Memorial
Memorial connects past and present.  When the Eucharist is described as a memorial it does not mean a simple commemoration of a past event, but an active remembering that enables the power of that event to be present for us here and now.  In the Eucharist the Church recalls the paschal mystery - Jesus’ suffering, death, resurrection and ascension - and makes it sacramentally present for our salvation. The proper term for this is a Greek word, anamnesis.
 
Memorial acclamation
The memorial acclamation is the congregation’s response to the priest’s announcement “The mystery of faith” after the Institution Narrative.  There are three forms of this acclamation.
 
Passover
The Passover is the annual ritual celebrated by faithful Jews in memory of the original liberation from Egypt and journey to the Promised Land (the exodus).   For Christians it takes on the added meaning of Jesus’ suffering, death and resurrection and his passing over to the Father.
 
Paschal mystery
The paschal mystery is what lies at the heart of all the sacraments and every liturgical celebration: the saving passion, death, resurrection and ascension of Jesus Christ and the sending of the Holy Spirit.  At the Eucharist this dynamic mystery is made present for us so that we can live it out in our daily lives.
 
Paschal triduum
The Paschal Triduum refers to the annual series of liturgies held over three days to celebrate the paschal mystery: the Mass of the Lord’s Supper on Holy Thursday evening, the Celebration of the Passion of the Lord on Good Friday afternoon, the Easter Vigil on Holy Saturday night, and the Mass of the Resurrection on Easter Sunday.  These are not separate liturgies but one continuous celebration of the passion, death and resurrection of Christ.
 
Preface
The preface is the first section of the Eucharistic Prayer, beginning with the introductory dialogue (‘The Lord be with you’…) and concluding with the Sanctus or Holy, Holy, Holy acclamation. It is characterized by thanksgiving and praise for creation and/or redemption.  Because it may vary according to the season or celebration, there are more than ninety Prefaces in the current Missal.
 
Responsorial psalm
The first reading at Mass is followed by the responsorial psalm.  This consists of a few verses, usually three or four, taken from one of the psalms, interspersed with a short response.  The cantor sings (or the reader announces) the response which all present repeat immediately, and again after each verse of the psalm.
 
Sacrament
A sacrament is an action with word and symbol by which the church communicates the saving power of God in particular ways.  There are seven of these foundational symbolic rites formally recognized in the Catholic Church: baptism, confirmation, eucharist, marriage, orders, reconciliation, and anointing of the sick.
 
Sacrifice of the Mass
The Mass is called a sacrifice because it engages the church in the once-and-for-all self-sacrifice of Jesus Christ on Calvary.  Jesus’ whole life of service to God and people came to a climax with his death on the cross.  He chose to symbolise this self-sacrifice at the Last Supper by calling the bread his Body “given for you” and the wine his Blood “poured out for many.”  The Church continues to obey his command to “Do this in memory of me.”