11 The first novelty of biblical faith consists, as we have seen, in its image of God. The second, essentially connected to this, is found in the image of man. The biblical account of creation speaks of the solitude of Adam, the first man, and God's decision to give him a helper. Of all other creatures, not one is capable of being the helper that man needs, even though he has assigned a name to all the wild beasts and birds and thus made them fully a part of his life. So God forms woman from the rib of man. Now Adam finds the helper that he needed: “This at last is bone of my bones and flesh of my flesh” ( Gen 2:23). Here one might detect hints of ideas that are also found, for example, in the myth mentioned by Plato, according to which man was originally spherical, because he was complete in himself and self-sufficient. But as a punishment for pride, he was split in two by Zeus, so that now he longs for his other half, striving with all his being to possess it and thus regain his integrity. While the biblical narrative does not speak of punishment, the idea is certainly present that man is somehow incomplete, driven by nature to seek in another the part that can make him whole, the idea that only in communion with the opposite sex can he become “complete”. The biblical account thus concludes with a prophecy about Adam: “Therefore a man leaves his father and his mother and cleaves to his wife and they become one flesh” ( Gen 2:24). Two aspects of this are important. First, eros is somehow rooted in man's very nature; Adam is a seeker, who “abandons his mother and father” in order to find woman; only together do the two represent complete humanity and become “one flesh”. The second aspect is equally important. From the standpoint of creation, eros directs man towards marriage, to a bond which is unique and definitive; thus, and only thus, does it fulfil its deepest purpose. Corresponding to the image of a monotheistic God is monogamous marriage. Marriage based on exclusive and definitive love becomes the icon of the relationship between God and his people and vice versa. God's way of loving becomes the measure of human love. This close connection between eros and marriage in the Bible has practically no equivalent in extra-biblical literature.
Source: Deus Caritas Est (Vatican.va)