וְלֹֽא־אָבָ֞ה יְהוָ֤ה אֱלֹהֶ֙יךָ֙ לִשְׁמֹ֣עַ אֶל־בִּלְעָ֔ם וַיַּהֲפֹךְ֩ יְהוָ֨ה אֱלֹהֶ֧יךָ לְּךָ֛ אֶת־הַקְּלָלָ֖ה לִבְרָכָ֑ה כִּ֥י אֲהֵֽבְךָ֖ יְהוָ֥ה אֱלֹהֶֽיךָ׃
נאָר ה׳ דײַן גאָט האָט ניט געװאָלט צוהערן צו בלעָמען, און ה׳ דײַן גאָט האָט דיר פֿאַרקערט די קללה אין אַ ברכה; װײַל ה׳ דײַן גאָט האָט דיך ליב.
Mishneh Torah, Negative Mitzvot
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).
Sefer HaChinukh
That an Ammonite or a Moabite not enter the Congregation of the Lord: That we should not marry with the males of the Children of Ammon and Moav forever, and even after they convert, as it is stated (Deuteronomy 23:4), “An Ammonite or a Moabite may not come into the Congregation of the Lord forever.”