And David made him houses in the city of David, and prepared a place for the ark of God, and pitched for it a tent.
Houses — A palace consisting of many houses or apartments for his several wives and children.
A tent — He did not fetch the tabernacle of Moses from Gibeon, because he intended forthwith to build the temple.
 Of the sons of Kohath; Uriel the chief, and his brethren an hundred and twenty:
 And David called for Zadok and Abiathar the priests, and for the Levites, for Uriel, Asaiah, and Joel, Shemaiah, and Eliel, and Amminadab,
The Priests — Abiathar the high-priest, and Zadok the second priest.
 And with them their brethren of the second degree, Zechariah, Ben, and Jaaziel, and Shemiramoth, and Jehiel, and Unni, Eliab, and Benaiah, and Maaseiah, and Mattithiah, and Elipheleh, and Mikneiah, and Obededom, and Jeiel, the porters.
Second degree — The first rank of sacred musicians being those three famous persons named verse 17, next to whom were these here named.
Porters — who were to keep the doors of the tabernacle and courts, but with all were instructed in musick, that when these were free from attendance upon their proper office, they might not be idle nor unprofitable in God's house.
 And Zechariah, and Aziel, and Shemiramoth, and Jehiel, and Unni, and Eliab, and Maaseiah, and Benaiah, with psalteries on Alamoth;
Alamoth — Or, with Alamoth which is thought to be the name of an instrument of musick; or of a certain tune, or note, or part in musick. The certain signification of it is not now known; and the like may be said of Sheminith, verse 21.
 And Mattithiah, and Elipheleh, and Mikneiah, and Obededom, and Jeiel, and Azaziah, with harps on the Sheminith to excel.
To excel — Which word may be added to note the excellency of that instrument, or part of musick; or that there was a greater extension or elevation of the voice than in the former. This way of praising God by musical instruments, had not hitherto been in use. But David instituted it by divine direction, and added it to the other ordinances of that dispensation.
 And Chenaniah, chief of the Levites, was for song: he instructed about the song, because he was skilful.
For song — He was the moderator of the musick, instructing them when and how to lift up their voices, or change their notes, or make their stops.
 And Berechiah and Elkanah were doorkeepers for the ark.
Door-keepers — They were appointed to keep the door of the tent in which the ark was to be kept, that no unallowed person might press in and touch it; and in like manner they were to attend upon the ark in the way, and to guard it from the press and touch of prophane hands; for which end these two went before the ark, is their other two brethren mentioned in the close of verse 24, came after it.
 And it came to pass, when God helped the Levites that bare the ark of the covenant of the LORD, that they offered seven bullocks and seven rams.
Helped — Encouraging them in their work with some comfortable sign of his presence with them. In all our religious exercises, we must derive help from heaven. God's ministers that bare the vessels of the Lord, have special need of divine help in their ministrations, that God may be glorified thereby, and the people edified.
 And David was clothed with a robe of fine linen, and all the Levites that bare the ark, and the singers, and Chenaniah the master of the song with the singers: David also had upon him an ephod of linen.
Linen — With a linen ephod. This circumstance is repeated, because it was an unusual thing for one, who was no Levite, to wear a Levitical garment.