Numbers 8:22-24

New American Standard Bible

²² Then after that the Levites went in to perform their service in the tent of meeting before Aaron and his sons; just as the Lord had commanded Moses concerning the Levites, so they did to them.

Retirement for the Levites

²³ Now the Lord spoke to Moses, saying, ²⁴ “This is what applies to the Levites: from ^(A)twenty-five years old and upward ^[a]they shall enter to perform service in the work of the tent of meeting.