Christian tradition, following his teaching, has always proclaimed the sanctity of marriage. It has defined marriage as the fundamental relationship in which a man and woman, by total sharing with each other, seek their own growth in holiness and that of their children, and thus show forth the presence on earth of God's kingdom.

The definition of sanctity of marriage means how it’s viewed by people since the olden days was derived from the holy bible where God himself established the unity of the first man and woman. “Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh” (Gen. 2:24).

The sanctity of marriage is indicated by the statement in Genesis 2:24, that a man must leave his father and mother and cleave to his wife. This union is set apart, it is to be distinct from the previous relationship of parent and child.