Midrasz do Kapłańska 10:19

7) (Vayikra 10:19): "And Aaron spoke (vayedaber) to Moses": "dibbur" connotes "strong" speech, as in (Bamidbar 21:25): "And the people spoke (vayedaber) against G d and against Moses."

8) (Vayikra 10:19): "Now did they (Elazar and Ithamar, who are forbidden to officiate when onenim [mourners]) this day offer their sin-offering and their burnt-offering before the L–rd?" (It is I [the high-priest (who does officiate when an onein)] who did so.) "And if there had befallen me (even the death of other kin for whom I must become an onein) such as these (my sons) and I had eaten the sin-offering this day, would it be good in the eyes of he L–rd!" (for which reason I burnt it.) R. Nechemiah says that it was burned because of aninuth, (for which reason "these" is mentioned.)

9) What is the intent of "such as these"? I might think that only (the death of) sons forbids one (to eat) in (a state of) aninuth. Whence do I derive (the same) for all mentioned in that section (of aninuth), including (by Rabbinical enactment) one's brother and sister by his mother and his married sister? From "such as these." R. Yaakov says: I might think that Levites in a state of aninuth would be forbidden to sing (the Levitical songs); it is, therefore, written ("and if there had befallen) me." I (i.e., a Cohein) am forbidden in (a state of aninuth), but Levites in aninuth are not forbidden to sing.