After that the ark had rest - The Targum says, "These are they whom David set over the service of the singing, in the house of the sanctuary, or tabernacle of the Lord, at the time in which the ark was brought into it;" that is, when it was brought from the house of Obed-edom.
The genealogies of David‘s three chief singers, Heman, Asaph, and Ethan or Jeduthun.
1 Chronicles 6:32
They waited on their office - On the establishment and continuance of the choral service in the temple, see 2 Chronicles 5:12, 2 Chronicles 29:27-30; 2 Chronicles 35:15.
1 Chronicles 6:33
Heman - In general Asaph takes precedence of Heman and Jeduthun, but here Heman is placed first, because his family, that of the Kohathites, had the highest priestly rank, being the family which furnished the high priests (see 1 Chronicles 6:2-15).
Shemuel - i. e. “Samuel.” Our translators have here given the Hebrew, while elsewhere they give uniformlv the Greek, form of the name. We learn by this genealogy that Heman was Samuel‘s grandson.
1 Chronicles 6:39
His brother Asaph - Not “brother” in the ordinary sense of the term, since Asaph was the son of Berachiah, and a Gershonite, not a Kohathite. “Brother” here may mean “fellow-craftsman” (compare 1 Chronicles 25:7).
1 Chronicles 6:44
Ethan - Or Jeduthun (see the margin). Corruption will scarcely account for the two forms of the name, since Ethan is used persistently up to a certain point 1 Chronicles 15:19, after which we have uniformly “Jeduthun.” The case seems to be rather one in which a new name was taken after a while, which thenceforth superseded the old. Compare Abraham, Sarah, Joshua, Jehoiakim, Zedekiah, etc.