Nehemiah 13:1-3

On that same day, as the Book of Moses was being read to the people, the passage was found that said no Ammonite or Moabite should ever be permitted to enter the assembly of God. For they had not provided the Israelites with food and water in the wilderness. Instead, they hired Balaam to curse them, though our God turned the curse into a blessing. When this passage of the Law was read, all those of foreign descent were immediately excluded from the assembly.