Numbers 4:1-3

Authorized (King James) Version

4 And the Lord spake unto Moses and unto Aaron, saying, ² Take the sum of the sons of Kohath from among the sons of Levi, after their families, by the house of their fathers, ³ from thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.