Albert Barnes Commentary 1 Chronicles 9:10

"And of the priests: Jedaiah, and Jehoiarib, Jachin," — 1 Chronicles 9:10 (ASV)

“Jedaiah,” “Jehoiarib,” and “Jachin” are not names of individuals here, but of priestly families. From 1 Chronicles 24:7–17, it appears that Jehoiarib was the original head of the first course, Jedaiah of the second shift, and Jachin of the twenty-first.