Numbers 8: 23 Now the Lord spoke to Moses, saying, 24 “This is what applies to the Levites: from twenty-five years old and upward [a]they shall enter to perform service in the work of the tent of meeting. But at the age of fifty years they shall retire from service in the work and not work any more.
This one applies to sleep:
Psalm 127:2 It is vain for you to rise up early, To retire late, To eat the bread of painful labors; For He gives to His beloved even in his sleep.
