Numbers 8:24-26

Amplified Bible, Classic Edition

²⁴ This is what applies to the Levites: from twenty-five years old and upward they shall go in to perform the work of the service of the Tent of Meeting,

²⁵ And at the age of fifty years, they shall retire from the warfare of the service and serve no more,

²⁶ But shall help their brethren in the Tent of Meeting [attend to protecting the sacred things from being profaned], but shall do no regular or heavy service. Thus shall you direct the Levites in regard to their duties.