Deuteronomy 20:7
Ver. 7. And what man is there that hath betrothed a wife, and hath not taken her?.... 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 {m}:
let him go and return unto his house, lest he die in battle, and another man take her; or marry her.
{m} Misn. Sotah, ib. sect. 2.