What does becoming “one flesh” mean?

Answer:

"Therefore a man shall leave his father and mother and be joined to his wife, and they shall become one flesh" (Genesis 2:24).

This statement serves as the foundation for marriage. It is quoted or alluded to by many writers in the Bible.

• In arguing that marriage is a serious matter not to be destroyed by divorce, Malachi alludes to the fact that the husband and wife become one flesh to produce godly children in Malachi 2:14-16.
• Jesus quotes this verse to prove that married couples are not to divorce for just any reason in Matthew 19:3-9 and Mark 10:6-12.
• Paul quotes this verse to prove that prostitution is wrong in I Corinthians 6:15-20.
• Paul also uses this verse to prove that husbands and wives should treat each other with respect, care, and love in Ephesians 5:28-31.

Here is what we can learn from this verse:

Marriage involves two people: a man and a woman. For it to be just two, the man and the woman must separate themselves from the family who raised them. No longer are the parents in charge of their children's lives. The man and the woman are forming a new family.

To be married, the man and the woman are joined together. This is done through a special set of vows called a covenant. "Yet she is your companion and your wife by covenant" (Malachi 2:14). Those vows bind the two people's lives together. "For the woman who has a husband is bound by the law to her husband as long as he lives. But if the husband dies, she is released from the law of her husband" (Romans 7:2).

The result is that two individuals become one flesh. In a physical sense, this means they can now join together in sexual intercourse. "Marriage is honorable among all, and the bed undefiled; but fornicators and adulterers God will judge" (Hebrews 13:4). Sex is a type of joining between individuals. See "Marriage's Glue" for more about this. But far more is being hinted at here than just sex. The idea of "one" on a spiritual plane means united in purpose and goals. "I do not pray for these alone, but also for those who will believe in Me through their word; that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me" (John 17:20-21). Just as Christians become one with God, Jesus, and their fellow Christians, a husband and wife become one. It is no longer about what each individual wants but what the family needs. It is the idea that it doesn't matter if you talk to the husband or the wife; you'll get basically the same answer.

Being one excludes all others. That is why Jesus said, "No one can serve two masters; for either he will hate the one and love the other, or else he will be loyal to the one and despise the other. You cannot serve God and mammon" (Matthew 6:24). Being one with God excludes anything else from being first in your life. A husband and wife being one excludes all other people. That is why Paul said a man cannot join himself with a prostitute and not affect his relationship with Jesus (I Corinthians 6:16). There is no room for a sinful relationship and a righteous relationship in one person.