Deuteronomy 9:18-20

18And I fell down before Yhwh, as at the first, forty days and forty nights: I did neither eat bread, nor drink water, because of all your sins which ye sinned, in doing wickedly in the sight of Yhwh, to provoke him to anger.

19For I was afraid of the anger and hot displeasure, wherewith Yhwh was wroth against you to destroy you. But Yhwh hearkened unto me at that time also.

20And Yhwh was very angry with Aaron to have destroyed him: and I prayed for Aaron also the same time.