Charles Ellicott Commentary 1 Chronicles 16:4

"And he appointed certain of the Levites to minister before the ark of Jehovah, and to celebrate and to thank and praise Jehovah, the God of Israel:" — 1 Chronicles 16:4 (ASV)

And he appointed certain of the Levites. — This literally means put, placed (Genesis 3:12).

To minister. — This literally means ministering—that is, as ministers. The object of the appointment is defined by the words that follow: to remind, to thank, and to praise Jehovah, the God of Israel. Each verb expresses a distinct kind of duty in the service of song.

To record is the technical term for chanting the psalms that accompanied the sacrificial burning of the Azkârâh, that is, the part of the meat offering that was presented on the altar (Leviticus 2:2). (Compare the use of the cognate verb in the titles of Psalm 38 and Psalm 70.)

To thank was to perform psalms of invocation, and confession of benefits received.

To praise was to sing and play hymns of hallelujah such as Psalms 146-150.

These Levites were to minister in this way before the Ark in the sacred tent of Mount Zion.