2 Chronicles 35:3
And said unto the Levites that taught all Israel, which were holy unto the LORD, Put the holy ark in the house which Solomon the son of David king of Israel did build; it shall not be a burden upon your shoulders: serve now the LORD your God, and his people Israel,
The command was spoken in the course of Josiah's reforms to the Levites whose work was to teach all Israel and who were holy to the Lord. The holy ark was to be set inside the house that Solomon, the son of David king of Israel, had built, so that it would no longer have to be borne as a burden upon their shoulders. With the ark thus given its resting place, the Levites were freed to give themselves to serving the Lord their God and to serving His people Israel.