Genesis 2:24

Genesis 2
24 Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.

This verse is interesting because it speaks to the dynamics for the family unit. A son is always a son to his parents. However, when it is time to take a wife, he must become a man. Unfortunately, this man will always be seen as a boy to his parents. So the Lord seems to be explaining that the man and his wife must hold fast (cleave) to each other in order, and not to the parents, or in-laws.

As discussed previously Zion is made up of those that are of one mind and one heart. The Lord appears to be explaining that the man and the woman must be a Zion. In cleaving to each other they are of one mind and one heart, but in marriage there is added union of flesh, and only in the act of truly 'knowing' the other are children brought into this world.