On the basis of this promise, lifelong marriage is able to bring forth the very best in human beings because it is the source of so much hope and joy, and the context in which many people must also respond to the challenges and suffering of the human condition.
For this reason the Second Vatican Council described marriage as 'an intimate partnership of life and love'which was 'established by the Creator and endowed by him with its own proper laws (Gaudium et Spes 48). What a marriage is derives not just from social conventions but 'from the very nature of man and woman as they came from the hand of the Creator' (Catechism of the Catholic Church 1603).
God’s plan, from the beginning of creation, was that man and woman become 'one flesh' as a sign of communion between persons (Gen 2:24). The sexual union of husband and wife seals and celebrates their marriage promises and their willingness to welcome new human life
Marriage is also the natural basis of the family and thus of the care of children and the continuation of human society. Properly understood, marital love 'demands indissolubility and faithfulness in definitive mutual giving' (John Paul II, Familiaris Consortio: Apostolic Exhortation on the Family (1981) 13).
Catholics consider marriage to be a sacrament – an effective, visible sign of God’s grace – which tells of God’s faithful and creative love and makes it real in that couple’s lives. As a sacrament of the Church, ‘holy matrimony’ consecrates human love, sexuality, and procreation to a higher purpose.
It unites the couple to God and makes them a sign of his covenant with his people. It identifies the couple with Christ who has made their marriage a sign of his faithful and unbreakable love for his Church. It makes their family a ‘domestic church.'
Although divorce had been permitted with Judaism, Christ restored God’s original order of creation with its high ideals for marriage and family. Christ gave married couples the example and the strength to live marriage in 'the reign of God'(Catechism 1615).
As St Paul says: 'Husbands, love your wives as Christ loved the Church and gave himself up for her, that he might sanctify her.' (Eph 5:25). Just as God’s covenant with his people is ‘for keeps’, so, Jesus insisted, Christian marriage is indissoluble: 'what God has united, man must not divide' (Mt 19:6).