John Chrysostom (attributed)

If then because the wife is made of the man, and both one of one flesh, a man shall leave his father and his mother, then there should be yet greater affection between brothers and sisters, for these come of the same parents, but man and wife of different. But this is saying too much, because the ordinance of God is of more force than the law of nature. For God’s precepts are not subject to the law of nature, but nature bends to the precepts of God. Also brethren are born of one, that they should seek out different roads; but the man and the wife are born of different persons, that they should coalesce in one. The order of nature also follows the appointment of God. For as is the sap in trees, so is affection in man. The sap ascends from the roots into the leaves, and passes forth into the seed. Therefore parents love their children, but are not so loved of them, for the desire of a man is not towards his parents, but towards the sons whom he has begot; and this is what is said, Therefore shall a man leave his father and his mother, and shall cleave unto his wife.