John Calvin Commentary Deuteronomy 24:1

"When a man taketh a wife, and marrieth her, then it shall be, if she find no favor in his eyes, because he hath found some unseemly thing in her, that he shall write her a bill of divorcement, and give it in her hand, and send her out of his house." — Deuteronomy 24:1 (ASV)

Although what relates to divorce was granted as an indulgence to the Jews, Christ declares that it was never in accordance with the Law, because it is directly repugnant to the first institution of God, from which a perpetual and inviolable rule must be sought.

It is a common saying that the laws of nature are indissoluble. God has declared once for all that the bond of union between husband and wife is closer than that of parent and child; therefore, if a son cannot shake off the paternal yoke, no cause can permit the dissolution of the connection a man has with his wife.

From this, it appears how great the perverseness of that nation was, which could not be restrained from dissolving a most sacred and inviolable bond. Meanwhile, the Jews improperly concluded from their impunity that what God did not punish (because of the hardness of their hearts) was lawful. Instead, they should have considered, according to Christ's answer, that man is not at liberty to separate those whom God has joined together (Matthew 19:6).

Still, God chose to make a provision for women who were cruelly oppressed, for whom it was better to be set free at once than to groan beneath a cruel tyranny their whole lives. Thus, in Malachi, divorce is preferred to polygamy, since it would be a more tolerable condition to be divorced than to endure a harlot and a rival (Malachi 2:14).

And undoubtedly, the bill or certificate of divorce, while it cleared the woman from all disgrace, cast some reproach on the husband. For he who confesses that he puts away his wife because she does not please him brings himself under the accusation of both moroseness and inconstancy. For what gross levity and disgraceful inconstancy it shows, that a husband should be so offended by some imperfection or disease in his wife as to cast away from him half of himself!

We see, then, that husbands were indirectly condemned by the certificate of divorce, since they thus committed an injury against their wives who were chaste and, in other respects, what they should be. On these grounds, God in Isaiah, to take away from the Jews all basis for complaint, bids them produce the certificate of divorce, if He had given any to their mother (Isaiah 1:1); as if to say, that His reason for rejecting them was just, because they had treacherously turned to ungodliness.

Some interpreters do not read these three verses continuously, but suppose the sense to be complete at the end of the first, in which the husband testifies that he divorces his wife for no offense, but because her beauty does not satisfy his lust. If, however, we pay closer attention, we will see that it is only one provision of the Law, namely, that when a man has divorced his wife, it is not lawful for him to marry her again if she has married another. The reason for the law is that, by prostituting his wife, he would be, as far as it was in his power, acting like a procurer. In this view, it is said that she was defiled because he had contaminated her body; for the liberty which he gave her could not abolish the first institution of God but rather, as Christ teaches, gave cause for adultery (Matthew 5:31 and 19:9). Thus, the Israelites were reminded that, although they divorced their wives with impunity, this license was by no means excused before God.