Jamieson, Fausset and Brown on 2 Chronicles 35:8-9

8-9. his princes--These gave to the priests and Levites; as those of Hezekiah's princes (2Ch 30:24). They were ecclesiastical princes; namely, Hilkiah the high priest (2Ch 34:9). Zechariah, probably the second priest of the Eleazar (2Ki 16:18), and Jehiel, of the Ithamar line. And as the Levitical tribes were not yet sufficiently provided (2Ch 35:9), some of their eminent brethren who had been distinguished in Hezekiah's time (2Ch 31:12-15), gave a large additional contribution for the use of the Levites exclusively.