John Calvin Commentary Deuteronomy 25:5

"If brethren dwell together, and one of them die, and have no son, the wife of the dead shall not be married without unto a stranger: her husband`s brother shall go in unto her, and take her to him to wife, and perform the duty of a husband`s brother unto her." — Deuteronomy 25:5 (ASV)

The text says, If brethren dwell together, and one of them die. This law has some similarity with that which permits a betrothed man to return to the wife whom he has not yet formally taken; for the object of both is to preserve for every man what he possesses, so that he may not be obliged to leave it to strangers, but may have heirs from his own body. When a son succeeds his father, whom he represents, there seems to be hardly any change made.

From this, it is also clear how very pleasing it is to God that no one should be deprived of his property, since He even makes a provision for the dying, so that what they could not give up to others without regret and distress might be preserved for their offspring. Therefore, unless his kinsman should remedy the dead man’s childlessness, this inhumanity is considered a kind of theft. For, since being childless was a curse of God, it was a comfort in this situation to hope for a borrowed offspring, so that the man's name might not be completely extinguished.

Since we now understand the intention of the law, we must also observe that the word brethren does not mean actual brothers, but cousins and other kinsmen, whose marriage with the widow of a kinsman would not have been incestuous; otherwise, God would contradict Himself. But these two things are quite compatible: that no one should uncover the nakedness of his brother, and yet that a widow should not marry outside her husband’s family until she had raised up seed for him through some relative. In fact, Boaz did not marry Ruth because he was the brother of her deceased husband, but only his near kinsman.

If anyone should object that it is unlikely that other kinsmen would live together, I reply that this passage is incorrectly assumed to refer to actually living together, as if they lived in the same house. Instead, the precept is merely addressed to relatives whose close proximity made it convenient to take the widows into their own homes; for, if any lived far away, freedom was granted to both to seek the fulfillment of this provision elsewhere. Surely it is unlikely that God would have authorized an incestuous marriage, which He had previously expressed His abhorrence of.

Nor can it be doubted, as I have stated above, that a similar obligation was imposed upon the woman to offer herself to the kinsman of her former husband. Although this was a harsh requirement, she still seemed to owe this much to his memory: to willingly raise up seed for the deceased. Yet, if anyone thinks differently, I will not argue the point with him. If, however, she were not obliged to do so, it would be absurd for her to voluntarily impose herself. Nor was there any other reason for her to bring the kinsman to trial, from whom she had been rejected, except so that she might gain the freedom to marry into another family.

Yet it is unlikely that the kinsman was to be condemned to a shameful punishment without being allowed to make his defense, because sometimes valid reasons for refusal could be presented. This disgrace, therefore, was only a penalty for inhumanity or avarice. By giving up his shoe, he renounced his right as a kinsman and yielded it to another; for, by behaving so unkindly toward the dead, he became unworthy of receiving any of the benefits of his kinship.