Numbers
Chapters 8:23-26
Revised Version 1885
23And the Lord spake unto Moses, saying,
24This is that which belongeth unto the Levites: from twenty and five years old and upward they shall go in to wait upon the service in the work of the tent of meeting:
25and from the age of fifty years they shall cease waiting upon the work, and shall serve no more;
26but shall minister with their brethren in the tent of meeting, to keep the charge, and shall do no service. Thus shalt thou do unto the Levites touching their charges.