Deuteronomy 20:7

“And what man is there that hath betrothed a wife, and hath not taken her? etc.] Home to his house and bedded with her; has only betrothed her, but is not properly married to her, the nuptials are not completed; this the Jews understand of anyone betrothed to him, whether a virgin or a widow, or the wife of a deceased brother (yea, they say, if his brother is dead in war, he returns and comes home), but not of a former wife divorced and received again f244: let him go and return unto his house, lest he die in battle, and another man take her; or marry her.”

“20:7 someone else would marry her: In this situation, a man who died would be deprived of offspring to carry on his name, which was a great tragedy in ancient Israel.”

“betrothed a wife: It was customary among the Jews to contract matrimony, espouse, or betroth, and for a considerable time to leave the parties in the houses of the respective parents; and when the bridegroom had made proper preparations, then the bride was brought home to his house, and the marriage consummated. The provisions in this verse refer to a case of this kind; though the Jews extend it to him who had newly consummated his marriage, and even to him who had married his brother's wife. It was deemed a peculiar hardship for a person to be obliged to go to battle, who had left a house unfinished, newly purchased land half tilled, or a wife with whom he had just contracted marriage. Deu…”