Thematic Bible: Ammonites and moabites

No Ammonite or Moabite may participate in the assembly of the LORD, and none of their descendants shall be admitted to the assembly of the LORD, to the tenth generation, because they didn't come to meet you with food and water along the way as you were coming out of Egypt. Instead, they hired Beor's son Balaam from Pethor in Aram-naharaim to curse you. However, the LORD your God didn't listen to Balaam. The LORD your God turned Balaam's curse into a blessing, because the LORD your God loves you. read more.
Don't seek a peace treaty with them as long as you live.