37 David left Asaph and his coworkers with the Chest of the Covenant of God and in charge of the work of worship; they were responsible for the needs of worship around the clock. 38 He also assigned Obed-Edom and his sixty-eight relatives to help them. Obed-Edom son of Jeduthun and Hosah were in charge of the security guards. 39 The priest Zadok and his family of priests were assigned to the Tent of God at the sacred mound at Gibeon 40 to make sure that the services of morning and evening worship were conducted daily, complete with Whole-Burnt-Offerings offered on the Altar of Burnt Offering, as ordered in the Law of God, which was the norm for Israel. 41 With them were Heman, Jeduthun, and others specifically named, with the job description: "Give thanks to God, for his love never quits!"
Matthew Henry's Commentary on 1 Chronicles 16:37-41
Commentary on 1 Chronicles 16:37-43
(Read 1 Chronicles 16:37-43)
The worship of God ought to be the work of every day. David put it into order. At Jerusalem, where the ark was, Asaph and his brethren were to minister before the ark continually, with songs of praise. No sacrifices were offered there, nor incense burnt, because the altars were not there; but David's prayers were directed as incense, and the lifting up of his hands as the evening sacrifice. So early did spiritual worship take place of ceremonial. Yet the ceremonial worship, being of Divine institution, must by no means be omitted; therefore at Gibeon, at the altars, the priests attended; for their work was to sacrifice and burn incense; and that they did continually, morning and evening, according to the law of Moses. As the ceremonies were types of the mediation of Christ, the observance of them was of great consequence. The attendance of his appointed ministers is right in itself, and encourages the people.