I believe there is no closer relationship on earth than that of a man/husband and woman/wife. Because of this, I want to quote Genesis 2:18-24 (from the New King James Version). It is a rather long passage, but it is so important to meditate on it in light of your question.

“And the LORD God said, ‘It is NOT GOOD THAT MAN SHOULD BE ALONE; I WILL MAKE HIM A HELPER COMPARABLE TO HIM.’ Out of the ground the LORD God formed every beast of the field and every bird of the air, and brought them to Adam to see what he would call them. And whatever Adam called each living creature, that was its name….But for Adam there was NOT FOUND A HELPER COMPARABLE TO HIM. And the LORD God caused a deep sleep to fall on Adam, and he slept; and He took one of his ribs, and closed up the flesh in its place. Then the rib which the LORD God had taken from man HE MADE INTO A WOMAN, and He brought her to the man. 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.”

We could fill many pages in expounding on this wonderful portion of Scripture, but with our limited space we will confine ourselves to a few remarks relative to the words I put in bold. God knew that the Man (Adam) needed a HELPER; that is, someone who was LIKE HIM and who would COMPLIMENT HIM. Adam observed the animals that God created and failed to find a helper. God knew this would be the case so He put Adam into a deep sleep and formed a woman from his side and upon waking she was presented to Adam as his helper. Adam instinctively knew she was a special creation made just for him! As one has said, “She was not taken from Adam’s head to dominate him, nor from his feet to be trodden down, but from under his arm to be protected, and from near his heart to be loved.” She was the perfect HELPER and would make him COMPLETE. In verse 24 we have what has been called, “The institution of marriage,” for God designed Adam and Eve to be “husband and wife.” This relationship would be so close that they would be looked upon as “one flesh,” something that is never said about any other relationship between two people (such as “parent and a child” or a “brother and a sister”). As precious as it is to have a mother, father, sisters and brothers, the union of a man and woman supersedes them in every way. It is so intimate that it is a picture of the relationship between “Christ and His church” (see Ephesians 5:22-32). This makes it clear that the relationship of a husband and a wife takes top priority over one’s relationship with his parents and his siblings.

This last statement is illustrated in the words, “Therefore a man shall leave his father and mother and be joined to his wife.” Prior to their marriage, they may have lived at home with their parents (and brothers and sisters), but now they are told to leave home and begin a new home. This doesn’t mean they forget their parents, for they should still love them and honor them. It means they will now begin a new family unit where they themselves may become parents and raise their children on their own.

One may be thinking, “All that has been said is well-known and elementary.” I would submit it isn’t as “well-known and elementary” as one might think, for today marriage and family has been “redefined” (with the introduction of same-sex marriages). Also, I see more and more where couples are married and they live with a set of parents (usually to “save money”). This has led to untold trouble and all because they have not obeyed the scripture to “leave father and mother.”

I know you wanted to see examples of this throughout the Bible, but that would be beyond the scope of our limited space. I would encourage you to read of Abraham and Sarah, Isaac and Rebecca, Jacob and Rachel, and many other married couples in Scripture. In each case they were “one flesh” (which speaks not just of their physical union, but of their total commitment to one another and the fellowship they enjoyed as man and wife). They did indeed “leave father and mother” and established their own home, giving top priority to one another over the other relationships they had with parents and siblings. (325.3) (DO)