Joseph Benson's Commentary of the Old and New Testaments - Deuteronomy 23:3
Deuteronomy 23:3. An Ammonite or a Moabite The Jews will have it, that the women of these two nations were not concerned in this law. And that though an Israelitish woman might not marry an Ammonite or Moabite, yet a man of Israel might marry one of their women, after she professed the Jewish religion. For ever This seems to denote the perpetuity of this law, that it should be inviolably observed in all succeeding ages. read more
Albert Barnes' Notes on the Whole Bible - Deuteronomy 23:9-14
The whole passage refers not to the encampments of the nation while passing from Egypt through the wilderness, but to future warlike expeditions seat out from Canaan. read more