2 Chronicles 31:16-17

¹⁶besides them that were reckoned by genealogy of males, from three years old and upward, even every one that entered into the house of Jehovah, as the duty of every day required, for their service in their offices according to their courses; ¹⁷and them that were reckoned by genealogy of the priests by their fathers` houses, and the Levites from twenty years old and upward, in their offices by their courses;