'Three Days and Three Nights' in the Bible

and they gave him a piece of a fig cake and two clusters of raisins; and when he had eaten, his energy returned, for he had not eaten bread or had any water to drink for three days and three nights.

Now the Lord had prepared (appointed, destined) a great fish to swallow Jonah. And Jonah was in the stomach of the fish three days and three nights.

for just as Jonah was three days and three nights in the belly of the sea monster, so will the Son of Man be three days and three nights in the heart of the earth.