I Chronicles 6:21

And they ministered before the dwelling place of the tabernacles of the congregation with singing,.... Psalms, hymns, and spiritual songs; this service they performed before the ark, which was in a tent or tabernacle David pitched for it; and which the Targum here calls the tabernacle of time, or a temporary tabernacle: until Solomon had built the house of the Lord in Jerusalem; the temple there: and then they waited on their office according to their order; performed it in the manner prescribed by David, see Ch1 25:1.

Though Joseph and Judah shared between them the forfeited honours of the birthright, yet Levi was first of all the tribes, dignified and distinguished with an honour more valuable than either the precedency or the double portion, and that was the priesthood. That tribe God set apart for himself; it was Moses's tribe, and perhaps for his sake was thus favoured. Of that tribe we have an account in this chapter. I. Their pedigree, the first fathers of the tribe (Ch1 6:1-3), the line of the priests, from Aaron to the captivity (Ch1 6:4-15), and of some other of their families (Ch1 6:16-30). II. Their work, the work of the Levites (v. 31-48), of the priests (Ch1 6:49-53). III. The cities appointed them in the land of Canaan (v. 54-81).