2 Chronicles 31:16
besides those from three years old and upward who as males were entered in the genealogical register, all that came into the house of Jehovah, as the duty of every day required, for their service in their charges, according to their divisions,
Ezra 3:4
And they held the feast of tabernacles as it is written, and offered daily burnt-offerings by number, according to the ordinance, as the duty of every day required;
Leviticus 21:22-23
The bread of his God, of the most holy and of the holy, shall he eat;
1 Chronicles 23:3
And the Levites were numbered from thirty years old and upward; and their number, by their polls, man by man, was thirty-eight thousand.