Deuteronomy 9:18; Deuteronomy 9:25

18 Then once again I fell prostrate before the LORD for forty days and forty nights; I ate no bread and drank no water, because of all the sin you had committed, doing what was evil in the LORD’s sight and so arousing his anger.

25 I lay prostrate before the LORD those forty days and forty nights because the LORD had said he would destroy you.