On that day, when the scroll from Moses was being read to the people, they found written in it that no Ammonite or Moabite should ever enter God's assembly.
References for Nehemiah 13:1
This is because they hadn't met the Israelites with food and water but instead hired Balaam against them to curse them. Yet our God turned the curse into a blessing.
When the people heard this law, they separated out from Israel all those of mixed descent.
Now before this, however, Eliashib the priest, who was appointed to be in charge of the storerooms of our God's house and who was related to Tobiah,
prepared a large room for Tobiah to use. This was the room where they had previously kept the grain offering, the incense, and the equipment, together with the tenth-part gifts of grain, wine, and oil. These items were for the Levites, singers, and gatekeepers as well as the portions for the priests.