Numbers 4:21-23

New Revised Standard Version, Anglicised

The Gershonites and Merarites

²¹ Then the Lord spoke to Moses, saying: ²² Take a census of the Gershonites also, by their ancestral houses and by their clans; ²³ from thirty years old up to fifty years old you shall enrol them, all who qualify to do work in the tent of meeting.