Charles Ellicott Commentary 2 Chronicles 35:3

"And he said unto the Levites that taught all Israel, that were holy unto Jehovah, Put the holy ark in the house which Solomon the son of David king of Israel did build; there shall no more be a burden upon your shoulders: now serve Jehovah your God, and his people Israel." — 2 Chronicles 35:3 (ASV)

The Levites that taught all Israel. —In the law (Nehemiah 8:7; compare also 2 Chronicles 17:8–9).

Which were holy to the Lord. —Separated to His service (Exodus 28:36, Holiness to the Lord, the inscription on Aaron’s mitre).

Put the holy ark in the house. —This command implies that the ark had been removed from its place in the inner sanctuary. The removal probably took place under Manasseh or his son, with the object of saving the sacred symbol from profanation. Or perhaps the repair of the Temple under Josiah had necessitated such a step. A third explanation takes the words in the sense of “Let the ark be, where it stands, in its proper place. Do not give a thought to your ancient function of bearing it about; but set your minds upon present duties.” This, however, is too artificial.

It shall not be a burden. —Literally, hearing on the shoulder is not for you. (Compare a similar statement in 1 Chronicles 23:26; Numbers 7:9; 1 Chronicles 15:2).

Serve now the Lord ... and his people. —In the manner indicated in 2 Chronicles 35:4–6.