What Does Genesis 2:21 Mean?

"Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh." The narrator interrupts the garden account to draw out the marriage pattern established in the first union. The etiological formula "therefore" reaches forward from the first marriage to every subsequent marriage: what happened in the garden between the man and his wife is the pattern for what happens in every household between every husband and wife. Genesis 2 grounds marriage in creation, not in social custom or cultural arrangement.

The pattern is surprising in its direction: the man leaves his father and mother, not the woman. In the ancient Near Eastern world, women typically left their families to join their husbands. The reversal here, the man is the one who leaves, marks the marriage bond as the superseding loyalty. Whatever the man's obligations to his parents, the bond to his wife is primary. The new family formed in marriage takes precedence over the family of origin in which both partners grew up.

"One flesh" (Hebrew: basar echad) describes the reality of the marriage union: two become one in a union that is real, specifically metaphorical. The flesh of the woman came from the flesh of the man; in marriage, what was divided is reunited. Paul quotes this verse in the context of sexual ethics (1 Corinthians 6:16) and in the context of marriage as a mystery of the Christ-church union (Ephesians 5:31-32). The "one flesh" of Genesis 2 is the model of the deepest union in the biblical story: the union of Christ with his people.