Deuteronomy 23:3 - Joseph Benson’s Commentary on the Old and New Testaments

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.