What does the Bible mean when it says a husband and wife become “one flesh”? This phrase describing marriage is variously understood, leading to different conclusions in debates about divorce and remarriage.

Here are some conclusions I’m drawing about what the phrase “one flesh” means:

1. It expresses the reality that woman and man are “made of the same stuff.” This is clear from the context where the phrase first occurs in Genesis 2:22-24:
   

   And the rib that the Lord God had taken from the man he made into a woman and brought her to the man. Then the man said,

   “This at last is bone of my bones
       and flesh of my flesh;
   she shall be called Woman,
       because she was taken out of Man.”

   Therefore a man shall leave his father and his mother and hold fast to his wife, and they shall become one flesh.

   The basic sequence is clear: (1) God makes woman from man’s body; (2) the man recognizes that the woman was “taken out of” his body and therefore in some way belongs to him; (3) it is because of this same-source likeness that a man and a woman become “one flesh” today.

2. But it also hints of a compatible difference. Since Eve was taken out of Adam, they fit back together a little like a single two-piece puzzle picture. God did not present Adam with someone identical to him, but rather someone who fit him–who completed him–who was compatible because she was different-yet-same. None of these descriptions are sufficient and every one of them can be abused, but the basic duality of gender difference is everywhere in the original context of our “one flesh” phrase: man/woman, Adam/Eve, father/mother, husband/wife.
3. It refers to physical oneness, especially sexual union. This is clear from the original context, which emphasizes the physicality of Adam (his body) and his wife (made from his body). The language of “bones” and “flesh” underscores this physical emphasis, as does Paul’s use of the term “one flesh” to show that “he who is joined to a prostitute becomes one body with her” (1 Cor. 6:16). Some commentators point out that Genesis doesn’t say Adam “knew” his wife until chapter 2, after the comment about being one flesh. Therefore, they say, the term refers to something that was real before (and therefore apart from) any sexual union. But that is an invalid argument. First, surely the patriarchs “knew” their wives far more often than the Bible mentions! Second, the term “one flesh” is first used not to refer directly to Adam and Eve, but to how men and women ever since have become one flesh in marriage. Therefore, whether or not Adam and Eve “knew” each other immediately upon first meeting each other is irrelevant to the definition of “one flesh.”
4. But it probably also refers to other kinds of oneness that unified bodies embody. This is suggested by how the Hebrew term for “flesh” is sometimes used elsewhere. Commentator Westermann says “the Hebrew בשׂר [flesh] does not stand in opposition to spirit or soul, like the Greek σάρξ [sarx, flesh], but describes human existence as a whole under the aspect of corporality [body-ness].”¹ In other words, the word “flesh,” though explicitly referring to bodies, can implicitly refer to humans (or even animals) as whole beings. Consider how the term “all flesh” is used throughout the OT: God talks about destroying “all flesh” in the flood (Gen. 6:13); he is described as “the God of the spirits of all flesh” (Num. 27:16); and “all flesh” will see God’s glory and worship him (Isa. 40:6; 66:23). In these passages “all flesh” is roughly equivalent to “all humanity,” and flesh is described as having spirits and being capable of worship. This suggests the possibility that becoming “one flesh” could mean becoming “one human.”
5. It is probably related to traditional Jewish language that expresses blood relationships and family ties. Adam says Eve is “bone of my bones and flesh of my flesh.” Similarly, the phrase “my bone and my flesh” was used by Laban to describe his nephew Jacob (Gen. 29:14) and by others in similar situations (Judg. 9:2; 2Sam. 5:1; 19:12-13). If someone is flesh of my flesh they are part of my family; if someone becomes one flesh with me, it might mean that we have formed a new family. This possibility is reinforced by the language of “leaving” and “cleaving” in the Genesis passage; the man leaves his birth family and forms a new family bond. Commentator Wenham emphasizes that the “one flesh” language means that “just as blood relations are one’s flesh and bone…, so marriage creates a similar kinship relation between man and wife. They become related to each other as brother and sister are.”²
6. But it actually expresses a relationship that is closer than any blood relationship. Here Wenham’s emphasis seems imbalanced. He acknowledges that becoming one flesh involves sexual union, shared children, and a spiritual and emotional relationship, but he emphasizes that it refers to a kinship tie formed in marriage. He even points to this one flesh relationship of a husband and wife as the reason for Deuteronomy 24’s prohibition on a divorced couples remarrying each other: “A man may not remarry his wife because his first marriage to her made her into one of his closest relatives… The partners to a marriage become one flesh.” Thus, to restore the marriage would be “a type of incest.”³ If this is true, then why is it not incest for any married couple to continue to have sexual relations with each other after their initial union has made them one flesh?

(Update: Wenham has now abandoned this interpretation of Deuteronomy 24 as guarding against incest, saying it is not “plausible.” He now says the command was designed to prevent the original husband from charging his wife with “some indecency” as “a ploy to acquire her dowry” that she would later receive from her second husband.⁴)

Apparently a one flesh union is not the same thing as a kinship bond, despite some similarities. I suggest that the difference is not that a husband and wife remain distant enough that sexual union is permissible, but that sexual union is permissible because they are closer than any other kinship bond. When Paul talks about a man and a woman becoming one flesh, he says that a man who loves his wife “loves himself”; he should care for her as for his own body and cherish her as “his own flesh” (Eph. 5:28-33). In fact, the one flesh union of a man and woman (even a prostitute) is compared to how we are “members” of Christ’s body–actually part of the same body as him (1 Cor. 6:15; Eph. 5:30). Jesus said that a married couple are so unified that “they are no longer two but one flesh” (Matt. 19:6).

In summary, my current best understanding of the Bible’s “one flesh” language is that it indicates the formation of a new two-in-one human being. One flesh union is possible because men and women are “made of the same stuff” and designed to fit each other. Our sexual union embodies and enables a more general profound oneness. This union is intended for marriage but can be experienced (contrary to God’s intent) outside of marriage. In one flesh union a new family bond is produced, but the union goes beyond mere kinship so that the best way to describe a one flesh couple is to say “they are no longer two.”

Commentator Provain paints a similar picture:

Adam is cut in half, so that there come into existence two ‘sides’. One becomes male and the other female. These are now separate beings, who nonetheless exist in the closest possible relationship; she is, as the male affirms, ‘bone of my bones and flesh of my flesh’ (2.23). Elsewhere in the OT, this combination of ‘bone’ and ‘flesh’ refers to a member of one’s family (e.g. Gen. 29.14). In Genesis 2 the language has an even more intimate significance, for the male and the female are destined to become again ‘one flesh’ in marriage (Genesis 2.24) – to ‘return’, as it were, to their original condition as the inhabitants of one body.⁵

Different understandings of the “one flesh” language of Genesis 2 can lead to different conclusions about divorce and remarriage today.

Here are two examples:

1. Gordon Wenham, in part because of what he believes [Update: “believed”] about a “one flesh” marriage union producing a permanent kinship relationship, feels that even today “it would seem wisest” for a divorced and remarried person “to adhere to the Deuteronomic” regulation and not return to their first spouse.⁶
2. Warren Wiersbe, who believes that the “one flesh” language implies that “marriage is basically a physical relationship,” concludes that “the phrase ‘one flesh’ implies that anything that breaks the physical bond in marriage can also break the marriage itself.”⁷

I am not sure either of those applications are essential conclusions of those specific understandings of the term “one flesh.”  I am also not sure what all practical conclusions should be drawn from this phrase. This one phrase cannot bear the weight of all our divorce and remarriage questions–particularly questions about what should happen next after God’s original design has been marred.

This phrase does, however, suggest very practical implications: If the “one flesh” summary statement means that God intends to form new two-in-one human beings, then monogamous, life-long marriage is clearly the creation norm. Why would you want to experience the personal fragmentation of sexual union with more than one partner? Why not rather invest “selfishly” in the health of your marriage and the good of your marriage partner (“yourself”) for as long as you both live?

What do you think the term “one flesh” means? What understandings have you heard of? What conclusions have you seen people make based on their understanding of this term? Please let me know if I’m missing something. Share your thoughts in the comments below. Thanks for reading!

If you want to support more writing like this, please leave a gift: