Ira - was a chief ruler about David - The Hebrew is כהן לדויד cohen ledavid, a priest to David; and so the Vulgate, Septuagint, Syriac, and Arabic. The Chaldee has רב rab, a prince, or chief. He was probably a sort of domestic chaplain to the king. We know that the kings of Judah had their seers, which is nearly the same: Gad was David’s seer, 2Sa 24:11, and Jeduthun was the seer of King Josiah, 2Ch 35:16.
The conclusion of this chapter is very similar to the conclusion of 2Sa 8:16-18 (note), where see the notes.