Biblical Answer

The phrase "one flesh" is a biblical concept that refers to the union of a man and woman in marriage. This union is not just physical, but also legal, emotional, and spiritual. In Genesis 2:24, it is written, "Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh." This verse sets the foundation for the biblical understanding of marriage as a union of two people becoming one.

The concept of "one flesh" is further developed in Ephesians 5:28-32, where Paul writes, "For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh." Here, Paul is not only referring to the physical union of marriage, but also to the spiritual union between Christ and the church. This union is described as a mystery that is profound, and one that is meant to illustrate the spiritual union between believers and God.

In the context of marriage, the phrase "one flesh" points to the idea that sex is a sign of the personal and legal union between a man and woman. It is a means to accomplish this union, and is not to be separated from it. As Paul writes in 1 Corinthians 6:16, "Do you not know that he who is joined to a prostitute becomes one body with her? For, as it is written, 'The two shall become one flesh.'" Here, Paul is warning against physical union without spiritual union, and emphasizing the importance of the union of marriage as a whole. In summary, the phrase "one flesh" refers to the biblical concept of marriage as a union of two people becoming one, physically, legally, emotionally, and spiritually.