Numbers 4:30

From thirty years old and upward even unto fifty years old shalt thou number them, every one that entereth into the service, to do the work of the tabernacle of the congregation.

Ver. 30. From thirty years.] The Greek hath it, from twenty-five years: for then they began to be learners and probationers; and at thirty, they set upon the service. See Numbers 8:24. In their old age they had leave to retire.