Commentary for I Chronicles 24:2

And Nadab and Abihu died, etc., and they had no sons Since they had no sons, Eleazar and Ithamar served as priests in their stead, but if Nadab and Abihu had had children, they would have preceded Eleazar and Ithamar in the high priesthood, for so we find with Ezra (3:9), for Jehozadak was Joshua’s father, and Jehozadak and Ezra were the sons of Seraiah, as it is written: (above 5:41): “... and Seraiah begot Jehozadak.” And in Ezra (7:1), it is written: “Ezra the son of Seraiah.” And Jehozadak went into exile to Babylon, and when they came up from Babylon, Joshua went up and served, but Ezra did not serve because Jehozadak was the firstborn, and the son of his firstborn brother preceded him, as is written in the prophecy of Haggai (1:1): “Joshua the son of Jehozadak, the High Priest.”