Rashi on Deuteronomy 9:20/רש"י על דברים ט׳:כ׳

1ובאהרן התאנף ה׳ AND WITH AARON THE LORD WAS ANGRY, because he listened to you.

2להשמידו TO DESTROY HIM — this denotes the extermination of one’s children, and so, too, it states, (Amos 2:9) “And I destroyed (ואשמיד) his fruit (offspring) from above” (Leviticus Rabbah 7:1).

3.(אחרי מות AND I PRAYED FOR AARON ALSO, and my prayer availed to atone half, so that only two of his sons died, and two remained alive.