Deuteronomy 9:9, 18

When I went up the mountain to receive the tablets of stone, the tablets of the covenant which the LORD made with you, I remained on the mountain forty days and forty nights; I did not eat food or drink water.

Then, as before, I fell down before the LORD for [another] forty days and forty nights; I did not eat food or drink water, because of all the sin you had committed by doing what was evil in the sight of the LORD to provoke Him to anger.