2 Chronicles 31:16
They were appointed to distribute them to males who were at least three years old. The way they were enrolled in the genealogical records did not matter. The six men who served under Kore were to distribute the offerings to everyone who went to Jehovah's Temple to perform the daily service that each division was responsible for.
Ezra 3:4
They celebrated the Festival of Booths according to what is written. Each day they offered the sacrifices required for that day.
Leviticus 21:22-23
He may eat the food of his God, what is holy and what is very holy.
1 Chronicles 23:3
The Levites thirty years old or older were counted, and the total number of men was thirty-eight thousand.