Albert Barnes Commentary 2 Samuel 20:26

"and also Ira the Jairite was chief minister unto David." — 2 Samuel 20:26 (ASV)

Ira the Jairite - He is not mentioned before this. He is perhaps the same person as “Ira an Ithrite” (a name found in a marginal note in some Bibles), that is, an inhabitant of Jattir in the hill country of Judah (Joshua 15:48; 1 Samuel 30:27). It is possible that “Ithrite” should be read here instead of “Jairite.”

A chief ruler ... about David - This phrase can be translated more simply and clearly as “was David’s kohen” (see the note on 2 Samuel 8:18). In the early part of David’s reign, his own sons were כהן kôhên (chief rulers). The deaths of Amnon and Absalom, and the dissensions in the family, had probably caused the change of policy in this respect.