Le Deutéronome 23:7 Halakha : Mishneh Torah, Kings and Wars, Mishneh Torah, Negative Mitzvot & Sefer HaChinukh

We do not extend offers of peace neither to Ammon nor to Moab, as it says, “do not seek as to their peace or their prosperity all your days” (Deut. 23:7). Our Sages have said that from what it says, “and you shall call upon her (the city) to peace” (Deut. 20:10) we might have thought that we can offer Ammon and Moab peace, were it not to say “do not seek their peace”. From the phrase, “With you he shall dwell…and you shall not wrong him” (Deut. 23:17) one would think that we can offer peace to Ammon and Moab. However, from the phrase, “and for their prosperity” we learn that although we do not offer them peace if they, on their own, make peace, we accept them.

Not to exclude a descendant of Esau from the community of Israel for three generations, as it is said, “Thou shalt not abhor an Edomite …. (the children that are begotten of them shall enter into the congregation of the Lord in their third generation)” (Deut. 23:8-9).

Not to offer peace to the Ammonites and Moabites before waging war on them, as should be done to other nations, as it is said, “Thou shalt not seek their peace and prosperity (all thy days for ever)” (Deut. 23:7; Authorized English version: 23:6).