Nehemiah 13:1-3

1On that day they read in the book of Moses in the audience of the people; and therein was found written, that an Ammonite and a Moabite should not enter into the assembly of God for ever, 2because they met not the children of Israel with bread and with water, but hired Balaam against them, to curse them: howbeit our God turned the curse into a blessing. 3And it came to pass, when they had heard the law, that they separated from Israel all the mixed multitude.