Why Moses Prayer Saved Only Half of Aaron's Sons

[After the death of the two sons of Aaron (Lev. 16:1).] All four were fit to die, but Moses prayed for them, and his prayer accomplished half. When? At the time when Israel made the calf. What is written there? "And the LORD was very angry with Aaron, to destroy him" (Deut. 9:20). And "destruction" is nothing other than annihilation, as it is said, "And I destroyed his fruit from above" (Amos 2:9). Once Moses prayed, his prayer accomplished half.