Deuteronomy 9:9-11

9When I went up on the mountain to get the stone tablets, the tablets of the promise that the Lord made to you, I stayed on the mountain 40 days and 40 nights without food or water.

10Then the Lord gave me the two stone tablets inscribed by God himself. On them were written all the words that the Lord spoke to you from the fire on the mountain on the day of the assembly.

11At the end of the 40 days and 40 nights, the Lord gave me the two stone tablets with his promise on them.