Albert Barnes Commentary Nehemiah 12:1

"Now these are the priests and the Levites that went up with Zerubbabel the son of Shealtiel, and Jeshua: Seraiah, Jeremiah, Ezra," — Nehemiah 12:1 (ASV)

The priests - The number of the names here given, which is 22, is probably to be connected with that of the Davidic “courses,” which was 24 (1 Chronicles 24:7–18). Eight names are identical with those of the heads in David’s time.

On comparing the present list with that of the families who sealed to Nehemiah’s covenant (Nehemiah 10:2–8), we will find that the first sixteen recur in that document nearly in the same order, but that the last six are absent from it. It would seem that because these six declined to seal to Nehemiah’s covenant, they were placed below the rest here in a sort of supplementary list. Note especially the “and” which connects the second part of the lists with the earlier part, both in Nehemiah 12:6 and in Nehemiah 12:19.