What does Genesis 2:24 speak of when it says “Therefore a man leaves his father and his mother and clings to his wife, and they become one flesh”? In particular, what does the text mean when it says that they become “one flesh?” The meaning of the text is further amplified by the previous verse, Genesis 2:23, where the man says, upon meeting the woman, “This at least is bone of my bones and flesh of my flesh.” A simple scan of other places in the Old Testament that speak of “flesh and bone” yields some interesting results:
- Genesis 29:14 and Laban said to him, “Surely you are my bone and my flesh!” And he stayed with him a month.
- Judges 9:2 “Say in the hearing of all the lords of Shechem, ‘Which is better for you, that all seventy of the sons of Jerubbaal rule over you, or that one rule over you?’ Remember also that I am your bone and your flesh.”
- 2 Samuel 5:1 Then all the tribes of Israel came to David at Hebron, and said, “Look, we are your bone and flesh.
- 2 Samuel 19:12 You are my kin, you are my bone and my flesh; why then should you be the last to bring back the king?’
- 2 Samuel 19:13 And say to Amasa, ‘Are you not my bone and my flesh? So may God do to me, and more, if you are not the commander of my army from now on, in place of Joab.'”
- 1 Chronicles 11:1 Then all Israel gathered together to David at Hebron and said, “See, we are your bone and flesh.
In each of these cases, the reference to “flesh and bone” is a reference to shared kinship. To be “one flesh” is to be in a relationship of kinship. This is clearly the meaning that Jesus also had in mind when asked about divorce in Matt 19:5f. and Mark 10:8. The fact that “the two become one flesh” means that the will of God never countenances divorce, which is essentially the severing of kinship ties and obligations.
Genesis 2 18ff. is thus about the origin of the most fundamental of social relationships that marked ancient society generally: the relationship of kinship. Gen. 2:24 narrates the close relationship between sexual union (“Therefore a man leaves his father and his mother and clings to his wife”) and the kinship relationship: “and they become one flesh.”
The basis for a biblical sexual ethic, therefore is simple. We are not to say with our bodies (by sexually uniting with another) what we are unable to say with the rest of our lives (by embracing the kinship bonds that such a union creates.)
In my book Bible, Gender, Sexuality, I explore in great detail what this core insight means for sexual ethics in general, and for the question of gay and lesbian relationships in particular.