What does the Bible say about oneness in marriage? The Bible is clear that the oneness God designed in marriage is unlike any other relationship, even that of parent and child. How is that possible? Look at Genesis 2:23-24. “And Adam said: ‘This is now 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 mother and be joined to his wife, and they shall become one flesh.” In Adam’s response to God’s gift to him, Eve (woman), we see an intense exclaim of delight. He sees in her one like himself, but also different—comparable and at the same time compatible.
Then we see how it is possible for this relationship between a man and a woman to be a greater bond than that of parent and child. It says that a man will leave his parents and be joined to his wife. A child will leave (meaning abandon) his or her parents and be joined (meaning glued to, cleave to) to the wife or husband. This joining is mental, emotional, physical, and sexual for both. It is designed as a oneness that no other human relationship comes close to. Now understand, this leaving, this abandoning, in no way severs the relationship between parent and child. It changes the order of it, as in who comes first. However, it also enhances it because now the child understands the relationship of his or her parents.
Later in the New Testament, we see Jesus use Genesis 2:24 in his response to questions about marriage. This response is found in Matthew 19:4-6 and Mark 10:6-9. In His response, Jesus adds, in both passages, “Therefore, what God has joined together, let no man separate.” This statement by Jesus speaks to the power and sacred nature of oneness in marriage.