Numbers 8:25
King James Version
“And from the age of fifty years they shall cease waiting upon the service and shall serve no more:”
Context
22And after that went the Levites in to do their service in the tabernacle of the congregation before Aaron, and before his sons: as the LORD had commanded Moses concerning the Levites, so did they unto them.
23And the LORD spake unto Moses, saying,
24This that unto the Levites: from twenty and five years old and upward they shall go in to wait upon the service of the tabernacle of the congregation:
25And from the age of fifty years they shall cease waiting upon the service and shall serve no more:
26But shall minister with their brethren in the tabernacle of the congregation, to keep the charge, and shall do no service. Thus shalt thou do unto the Levites touching their charge.