2 Chronicles 29:30
Moreover Hezekiah the king and the princes commanded the Levites to sing praise unto the LORD with the words of David, and of Asaph the seer. And they sang praises with gladness, and they bowed their heads and worshipped. Moreover Hezekiah the king and the princes commanded the Levites to sing praise unto the LORD with the words of David, and of Asaph the seer. And they sang praises with gladness, and they bowed their heads and worshipped.
The singing commanded in the verse belonged to the first service held after the cleansing of the temple. Sin offerings had first been placed upon the altar to make atonement for all Israel, and then the king and all who were present had bowed themselves and worshiped. Only after that humbling and atonement did the commanded praise begin.
At the command of Hezekiah the king and the princes, the Levites sang praise to the Lord with the words of David and of Asaph the seer. Their singing filled the temple courts again with praise and adoration. They sang praises with gladness and joy because they realized they were being delivered from the bondage of sin and apostasy.