The third consideration is marriage as covenant and sacrament. It is important to note that this third category includes the other two categories, the sexual and the social, and adds an additional dimension. By covenant we mean that marriage in scripture involves a relationship with God. In the ancient scriptures of the Hebrews the notion of covenant qualified the unique relationship God established with the Israelite people. The unusual aspect of this relationship was that human relations became imbued with divine significance. Thus offenses against one's neighbor became also offenses against the covenant. Doubtless people found stealing, lying and adultery negative experiences, especially for the victims, but now they become sins or offenses against God. God has an interest in maintaining the proper order within the covenant community.
Not only is marriage protected by divine sanction, but also marriage has a meaning relating to the very creation. In the Book of Genesis God creates the male and female as one reality. There is in the picture language of that work a unity prior to the later diversity into two different sexes. This means that there is a complementarity between the male and the female, so that alone they are not whole, but only find wholeness through the other. The two become one flesh. The natural physical bonding of sexuality, which we have discussed, the social commitment necessary for stability, takes on a deeply psychological and spiritual meaning. The partner is the other self.
Jesus approves of this early understanding of marriage before the advent of divorce, with the phrase "in the beginning." In other words, in the beginning there was such a unity of persons, divorce was not possible. Divorce would be cutting away a part of oneself. He also quotes: "A man shall leave his father and mother and be joined to his wife and become one flesh." This incidentally was not a description of the social custom of the Hebrews. In fact the wife came to live with the husband in the family cluster. What Jesus meant was the connection between a man and his wife had to be stronger and take precedence over the bond he had with his father and mother, which in a so-called patriarchal society was the strongest social bond. This was an ideal that may not have been realized often.
The Church's understanding of marriage grew for centuries. The transformation that comes about through faith and Baptism could not but influence marriage. Gradually the Church discerned that marriage exists in two forms, one natural and open to all people and the other supernatural and open to people who share the gift of faith. The supernatural form of marriage is called a sacrament and it is a sign of Christ's unity with the Church his bride. If marriage is a sacrament, then it is in and through marriage that Christ sanctifies married couples. They do not receive the sacrament from the priest but administer it to each other.
The Church teaches that the transmission of life is one of the highest purposes of marriage and that couples should always remain open to life. For serious reasons couples may use natural periods of infertility to regulate births, but not artificial contraception. In principle the unitive and the procreative goals or intents in marriage remain intrinsically connected.
As discussed above marriage requires both the man and the woman to sacrifice their egoism and many personal preferences. Such sacrifices may be motivated by the needs of children, but in Christian moral thought and teaching, the transformation of a person from self-centered to other-centered is a good in itself even apart from children. Catholics believe that it is God who inaugurates this transformation and who provides all necessary graces toward its accomplishment. Again God wants his children to be happy, joyful and prosperous. The sacramental graces of marriage or matrimony are ways God uses to bring that desire into fruition.