Deuteronomy 9:9, 18

When I went up into the mountain to receive the tablets of stone, the tablets of the covenant which the LORD made with you, then I stayed on the mountain forty days and forty nights. I neither ate bread nor drank water.

And I fell down before the LORD, as at the first, forty days and forty nights; I neither ate bread nor drank water, because of all your sin which you committed in doing wickedly in the sight of the LORD, to provoke Him to anger.