Deuteronomy 23:3-6

23:3 An Ammonite or Moabite may not enter the assembly of the Lord; to the tenth generation none of their descendants shall ever do so, 23:4 for they did not meet you with food and water on the way as you came from Egypt, and furthermore, they hired Balaam son of Beor of Pethor in Aram Naharaim to curse you. 23:5 But the Lord your God refused to listen to Balaam and changed the curse to a blessing, for the Lord your God loves you. 23:6 You must not seek peace and prosperity for them through all the ages to come.

Nehemiah 4:3-7

4:3 Then Tobiah the Ammonite, who was close by, said, “If even a fox were to climb up on what they are building, it would break down their wall of stones!”

4:4 Hear, O our God, for we are despised! Return their reproach on their own head! Reduce them to plunder in a land of exile! 4:5 Do not cover their iniquity, and do not wipe out their sin from before them. For they have bitterly offended the builders!

4:6 So we rebuilt the wall, and the entire wall was joined together up to half its height. The people were enthusiastic in their work.

4:7 (4:1) When Sanballat, Tobiah, the Arabs, the Ammonites, and the people of Ashdod heard that the restoration of the walls of Jerusalem had moved ahead and that the breaches had begun to be closed, they were very angry.

Nehemiah 13:1-3

Further Reforms by Nehemiah

13:1 On that day the book of Moses was read aloud in the hearing of the people. They found written in it that no Ammonite or Moabite may ever enter the assembly of God, 13:2 for they had not met the Israelites with food and water, but instead had hired Balaam to curse them. (Our God, however, turned the curse into blessing.) 13:3 When they heard the law, they removed from Israel all who were of mixed ancestry.