Talmud zu Dewarim 20:7

MISHNAH: “¹⁸⁰Deut. 20:7. Who is the man who became betrothed¹⁸¹He married her in the preliminary ceremony (Note 146) but did not take her into his house. to a woman and did not take her,” etc. Not only one betrothed to a virgin, even one betrothed to a widow, even to one who waits for her brother-in-law¹⁸²The widow of his childless brother. The surviving brother can marry her based on the dead brother’s preliminary marriage; but rabbinically one requires a new preliminary “bespeaking”, cf. Yebamot 2:1, Note 6. The next sentence shows that the Mishnah does not refer to this rabbinic ceremony.. Even if he heard that his brother had died in the war he then returns and leaves. All those who listen to the Cohen in the front lines return and provide food and water and improve the roads¹⁸³They serve the army in the rear..