Deuteronomy 23:3-4 Deut. 23:3-4
3 An Ammonite or Moabite shall not enter into the congregation of the LORD; even to their tenth generation shall they not enter into the congregation of the LORD for ever: 4 Because they met you not with bread and with water in the way, when ye came forth out of Egypt; and because they hired against thee Balaam the son of Beor of Pethor of Mesopotamia, to curse thee.
Nehemiah 13:23-27 Neh. 13:23-27
23 In those days also saw I Jews that had married wives of Ashdod, of Ammon, and of Moab: 24 And their children spake half in the speech of Ashdod, and could not speak in the Jews' language, but according to the language of each people. 25 And I contended with them, and cursed them, and smote certain of them, and plucked off their hair, and made them swear by God, saying, Ye shall not give your daughters unto their sons, nor take their daughters unto your sons, or for yourselves. 26 Did not Solomon king of Israel sin by these things? yet among many nations was there no king like him, who was beloved of his God, and God made him king over all Israel: nevertheless even him did outlandish women cause to sin. 27 Shall we then hearken unto you to do all this great evil, to transgress against our God in marrying strange wives?
(Relation)