Matthew Henry on 1 Chronicles 16:37–end
The worship of God is not only to be the work of a solemn day now and then, brought in to grace a triumph; but it ought to be the work of every day. David therefore settles it here for a constancy, puts it into a method, which he obliged those that officiated to observe in their respective posts. In the tabernacle of Moses, and afterwards in the temple of Solomon, the ark and the altar were together; but, ever since Eli's time, they had been separated, and still continued so till the temple was built. I cannot conceive what reason there was why David, who knew the law and was zealous for it, did not either bring the ark to Gibeon, where the tabernacle and the altar were, or bring them to Mou…
Read the whole note in the consoleJamieson-Fausset-Brown on 1 Chronicles 16:39
And Zadok . . . before the tabernacle . . . at Gibeon--While the above-mentioned officers under the superintendence of Abiathar, were appointed to officiate in Jerusalem, whither the ark had been brought, Zadok and the priests subordinate to him were stationed at Gibeon to perform the sacred service before the ancient tabernacle which still remained there.
Adam Clarke on 1 Chronicles 16:39
Zadok the priest - Both Zadok and Abiathar were high priests at this time: the former David established at Gibeah, or Gibeon, where the ark had been all the days of Saul; and the latter he established at Jerusalem, where the ark now was: so there were two high priests, and two distinct services; but there was only one ark. How long the service at Gibeon was continued we cannot tell; the principal functions were no doubt performed at Jerusalem.
John Gill on 1 Chronicles 16:39
And Zadok the priest, and his brethren the priests,.... These he left, having appointed them
to be before the tabernacle of the Lord, in the high place that was at Gibeon; namely, the tabernacle of Moses, which was removed from Nob thither in the days of Saul, and continued there to the times of Solomon, 1 Chronicles 21:28.