'Nights' in the Bible

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

It came about at the end of forty days and nights that the Lord gave me the two tablets of stone, the tablets of the covenant.

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

“So I fell down before the Lord the forty days and nights, which I did because the Lord had said He would destroy you.

“I, moreover, stayed on the mountain forty days and forty nights like the first time, and the Lord listened to me that time also; the Lord was not willing to destroy you.