Talmud Yerushalmi on The Death of the Sons of Aaron and Yom Kippur

"Rabbi Chiyah bar Ba says: The sons of Aaron died on the first day of Nissan, which was the eighth day of the miluim. So why does the Torah mention their deaths in the passage about the Yom Kippur service? To teach you that just as Yom Kippur atones for the sins of Israel, so do the deaths of righteous people atone for the sins of Israel."

-- Talmud Yerushalmi, Yoma 2b