Deuteronomy 9:9, 18

When I went up on the mountain to receive the tablets of stone, the tablets of the covenant that the LORD had made with you, I stayed on the mountain forty days and forty nights; I ate no bread and drank no water.

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.