Deuteronomy 9:9, 18

This happened when I was on the mountain receiving the tablets of stone inscribed with the words of the covenant that the LORD had made with you. I was there for forty days and forty nights, and all that time I ate no food and drank no water.

“Then, as before, I threw myself down before the LORD for forty days and nights. I ate no bread and drank no water because of the great sin you had committed by doing what the LORD hated, provoking him to anger.