Numbers 8:24-26

Brenton(i) 24 This is the ordinance for the Levites; From five and twenty years old and upward, they shall go in to minister in the tabernacle of witness. 25 And from fifty years old the Levites shall cease from the ministry, and shall not work any longer. 26 And his brother shall serve in the tabernacle of witness to keep charges, but he shall not do works: so shalt thou do to the Levites in their charges.