Numbers 4:20

¹⁸Cut ye not off the tribe of the families of the Kohathites from among the Levites:

¹⁹But thus do unto them, that they may live, and not die, when they approach unto the most holy things: Aaron and his sons shall go in, and appoint them every one to his service and to his burden:

— Numbers 4:20 —

²¹And the LORD spake unto Moses, saying,

²²Take also the sum of the sons of Gershon, throughout the houses of their fathers, by their families;