Ambrose of Milan
Catena Aurea · Lukasevangelium 16
And the Pharisees also, who were covetous, heard all these things: and they derided him. And he said unto them, Ye are they which justify yourselves before men; but God knoweth your hearts: for that which is highly esteemed among men is abomination in the sight of God. The Law and the Prophets were until John: since that time the kingdom of God is preached, and every man presseth into it. And it is easier for heaven and earth to pass, than one tittle of the law to fail. Whosoever putteth away his wife, and marrieth another, committeth adultery: and whosoever marrieth her that is put away from her husband committeth adultery.
But we must first speak, I think, of the law of marriage, that we may afterwards discuss the forbidding of divorce. Some think that all marriage is sanctioned by God, because it is written, Whom God hath joined, let not man put asunder. (Matt. 19:6.) How then does the Apostle say, If the unbelieving depart, let him depart? (Mark 10:9, 1 Cor. 7:15.) Herein he shews that the marriage of all is not from God. For neither by God’s approval are Christians joined with Gentiles. Do not then put away thy wife, lest thou deny God to be the Author of thy union. For if others, much more oughtest thou to bear with and correct the behaviour of thy wife. And if she is sent away pregnant with children, it is a hard thing to shut out the parent and keep the pledge; so as to add to the parents’ disgrace the loss also of filial affection. Harder still if because of the mother thou drivest away the children also. Wouldest thou suffer in thy lifetime thy children to be under a step-father, or when the mother was alive to be under a step-mother? How dangerous to expose to error the tender age of a young wife. How wicked to desert in old age one, the flower of whose growth thou hast blighted. Suppose that being divorced she does not marry, this also ought to be displeasing to you, to whom though an adulterer, she keeps her troth. Suppose she marries, her necessity is thy crime, and that which thou supposest marriage, is adultery.