I Chronicles 23:24

And also unto the Levites,.... Or with respect to them: they shall no more carry the tabernacle: on their shoulders, from place to place, as they had done: nor any vessels of it for the service thereof; and so the service of it did not require men at their full strength, but such as were but twenty years of age might be employed in it.

Here is, I. An alteration made in the computation of the effective men of the Levites - that whereas, in Moses's time, they were not enlisted, or taken into service, till they were thirty-years old, nor admitted as probationers till twenty-five (Num 8:24), David ordered, by direction from God, that they should be numbered for the service of the house of the Lord, from the age of twenty years and upwards, Ch1 23:24. This order he confirmed by his last words, Ch1 23:27. When he put his last hand to the draught of this establishment he expressly appointed this to be done for ever after; yet not he; but the Lord. 1. Perhaps the young Levites, having no work appointed them till twenty-five years old, had many of them got a habit of idleness, or grew addicted to their pleasures, which proved both a blemish to their reputation and a hindrance to their usefulness afterwards, to prevent which inconvenience they are set to work, and brought under discipline, at twenty-years old. Those that will be eminent must learn to take care and take care betimes. 2. When the work of the Levites was to carry burdens, heavy burdens, the tabernacle and the furniture of it, God would not call any to it till they had come to their full strength; for he considers our frame, and, in service as well as sufferings, will lay no more upon us than we are able to bear. But now God had given rest to his people, and made Jerusalem his dwelling-place for ever, so that there was no more occasion to carry the tabernacle and the vessels thereof, the service was much easier, and what would not over-work them nor over-load them if they entered upon it at twenty-years old. 3. Now the people of Israel were multiplied, and there was a more general resort to Jerusalem, and would be when the temple was built, than ha…

23:24-27 In the census of 23:3, individuals were counted at age thirty, but the actual registration of the divisions included those twenty years old or older (cp. Num 1:3). The age of entry into Levitical service apparently varied over time according to need.