And Moses went into the midst of the cloud, and gat him up into the mount: and Moses was in the mount forty days and forty nights. (24:18)

And he was there with the Lord forty days and forty nights; he did neither eat bread, nor drink water. And he wrote upon the tables the words of the covenant, the ten commandments. (34:28)

--Deuteronomy--

When I was gone up into the mount to receive the tables of stone, [even] the tables of the covenant which the Lord made with you, then I abode in the mount forty days and forty nights, I neither did eat bread nor drink water: (9:9)

Thus I fell down before the Lord forty days and forty nights, as I fell down [at the first]; because the Lord had said he would destroy you. (9:25)