Mark Dever on unity in the covenant of marriage:
The context of this unity of husband and wife is the covenant of marriage; we can tell by what we read here [Mark 10] that this is a hugely important covenant. In fact it’s so important…that it takes priority over other family relationships — with either your parents as it says in verse seven or even your own children. Do you know? You’re not one flesh with your children. Even if you’re a mother and that child came from your body, you are not one flesh with him. Christianity is clear in prioritizing and privileging marriage above every other aspect of the family. And we get that right from Jesus who gets that right from Genesis.
Words of Grace 