A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Chronicles 26:1
ch1 26:1DIVISIONS OF THE PORTERS. (Ch1 26:1-12)
Concerning the divisions of the porters--There were four thousand (Ch1 23:6), all taken from the families of the Kohathites and Merarites (Ch1 26:14), divided into twenty-four courses--as the priests and musicians.
Meshelemiah the son of Kore, of the sons of Asaph--Seven sons of Meshelemiah are mentioned (Ch1 26:2), whereas eighteen are given (Ch1 26:9), but in this latter number his relatives are included.
1 Chronicles 26:5
ch1 26:5God blessed him--that is, Obed-edom. The occasion of the blessing was his faithful custody of the ark (Sa2 6:11-12). The nature of the blessing (Psa 127:5) consisted in the great increase of progeny by which his house was distinguished; seventy-two descendants are reckoned.
1 Chronicles 26:6
ch1 26:6mighty men of valour--The circumstance of physical strength is prominently noticed in this chapter, as the office of the porters required them not only to act as sentinels of the sacred edifice and its precious furniture against attacks of plunderers or popular insurrection--to be, in fact, a military guard--but, after the temple was built, to open and shut the gates, which were extraordinarily large and ponderous.
1 Chronicles 26:10
ch1 26:10Simri the chief . . . though . . . not the first-born--probably because the family entitled to the right of primogeniture had died out, or because there were none of the existing families which could claim that right.
1 Chronicles 26:12
ch1 26:12Among these were the divisions of the porters, even among the chief men--These were charged with the duty of superintending the watches, being heads of the twenty-four courses of porters.
1 Chronicles 26:13
ch1 26:13THE GATES ASSIGNED BY LOT. (Ch1 26:13-19)
they cast lots--Their departments of duty, such as the gates they should attend to, were allotted in the same manner as those of the other Levitical bodies, and the names of the chiefs or captains are given, with the respective gates assigned them.
1 Chronicles 26:15
ch1 26:15the house of Asuppim--or, "collections," probably a storehouse, where were kept the grain, wine, and other offerings for the sustenance of the priests.
1 Chronicles 26:16
ch1 26:16the gate Shallecheth--probably the rubbish gate, through which all the accumulated filth and sweepings of the temple and its courts were poured out.
by the causeway of the going up--probably the ascending road which was cast up or raised from the deep valley between Mount Zion and Moriah, for the royal egress to the place of worship (Ch2 9:4).
ward against ward--Some refer these words to Shuppim and Hosah, whose duty it was to watch both the western gate and the gate Shallecheth, which was opposite, while others take it as a general statement applicable to all the guards, and intended to intimate that they were posted at regular distances from each other, or that they all mounted and relieved guard at the same time in uniform order.
1 Chronicles 26:17
ch1 26:17Eastward were six Levites--because the gate there was the most frequented. There were four at the north gate; four at the south, at the storehouse which was adjoining the south, and which had two entrance gates, one leading in a southwesterly direction to the city, and the other direct west, two porters each. At the Parbar towards the west, there were six men posted--four at the causeway or ascent (Ch1 26:16), and two at Parbar, amounting to twenty-four in all, who were kept daily on guard.
1 Chronicles 26:18
ch1 26:18Parbar--is, perhaps, the same as Parvar ("suburbs," Kg2 23:11), and if so, this gate might be so called as leading to the suburbs [CALMET].
1 Chronicles 26:20
ch1 26:20LEVITES THAT HAD CHARGE OF THE TREASURES. (Ch1 26:20-28)
of the Levites, Ahijah--The heading of this section is altogether strange as it stands, for it looks as if the sacred historian were going to commence a new subject different from the preceding. Besides, "Ahijah, whose name occurs after" the Levites, is not mentioned in the previous lists. It is totally unknown and is introduced abruptly without further information; and lastly, Ahijah must have united in his own person those very offices of which the occupants are named in the verses that follow. The reading is incorrect. The Septuagint has this very suitable heading, "And their Levitical brethren over the treasures," &c. [BERTHEAU]. The names of those who had charge of the treasure chambers at their respective wards are given, with a general description of the precious things committed to their trust. Those treasures were immense, consisting of the accumulated spoils of Israelitish victories, as well as of voluntary contributions made by David and the representatives of the people.
1 Chronicles 26:29
ch1 26:29OFFICERS AND JUDGES. (Ch1 26:29-32)
officers and judges--The word rendered "officers" is the term which signifies scribes or secretaries, so that the Levitical class here described were magistrates, who, attended by their clerks, exercised judicial functions; there were six thousand of them (Ch1 23:4), who probably acted like their brethren on the principle of rotation, and these were divided into three classes--one (Ch1 26:29) for the outward business over Israel; one (Ch1 26:30), consisting of seventeen hundred, for the west of Jordan "in all business of the Lord, and in the service of the king"; and the third (Ch1 26:31-32), consisting of twenty-seven hundred, "rulers for every matter pertaining to God, and affairs of the king."