John Calvin Commentary Deuteronomy 21:14

"And it shall be, if thou have no delight in her, then thou shalt let her go whither she will; but thou shalt not sell her at all for money, thou shalt not deal with her as a slave, because thou hast humbled her." — Deuteronomy 21:14 (ASV)

And it shall be, if you have no delight in her. I have been compelled to separate this sentence from the preceding context, which I have explained elsewhere;¹⁶¹ for Moses there gave instructions on how a captive woman was to be taken as a wife if her beauty attracted a Jewish husband. That law, then, related to chastity and conjugal fidelity, and especially to the purity of the worship of God; but now Moses prescribes that if a man has dishonored a captive woman, he should not sell her but should set her free, and by this act of satisfaction, erase, or at least diminish, the injury.

Therefore, we infer that this rule of justice is based on the Eighth Commandment: Let no one defraud another. This condition was at least tolerable for the captive woman; for although chastity is a special treasure, liberty—which is rightly called an inestimable blessing—was no small consolation to her. The penalty, then, for lust was that the conqueror would lose his booty.

¹⁶¹ Vide vol. 2, p. 70..