John Gill Commentary 1 Chronicles 16:41

"and with them Heman and Jeduthun, and the rest that were chosen, who were mentioned by name, to give thanks to Jehovah, because his lovingkindness [endureth] for ever;" — 1 Chronicles 16:41 (ASV)

And with them
That is, with Zadok, and the priests with him at Gibeon:

he left Heman and Jeduthun :
or Ethan, two principal singers:

and the rest that were chosen, who were expressed by name ;
see (1 Chronicles 16:18 1 Chronicles 16:20 1 Chronicles 16:21)

to give thanks to the Lord, because his mercy endureth for ever ;
to praise him for his benefits, flowing from his grace and mercy continually.