Why does the Targum say that Ira was from Teko'a?
Rashi: So it says below (23:26). He is called ha'Ya'iri 1 , for Teko'a was the best place for olive oil for the Menorah (it illuminates).
Radak: Or, his family's name was Ya'iri; his father or grandfather was Ya'ir.
Why does it say that he was "Kohen l'David"?
Rashi (from Eruvin 63a): David used to give all of his Matanos Kehunah to him 1 .
Rashi: He made him an officer and a judge.
Radak citing Targum Yonasan: He was a Rav to David, i.e. his mentor and advisor. This is like "Re'e ha'Melech" (Melachim I, 4:5). It cannot mean a descendant of Aharon, for it already mentioned Kohanim! Also, a Kohen is for all of Yisrael, and not only for David!
Radak: It already mentioned Kohanim - if so, "Kohen" does not mean Aharon's descendants!
