Adam Clarke on Ezekiel 44:10

And the Levites that are gone away far from me - This refers to the schism of Jeroboam, who, when he set up a new worship, got as many of the priests and Levites to join him in his idolatry as he could. These, on the return from the captivity, should not be permitted to perform the functions of priests in the new temple; but they might be continued as keepers of all the charge of the house - be treasurers, guards of the temple, porters, etc.; see Eze 44:11-15. The whole of these passages refer to the period of time when the second temple was built.