Mt 12:38-41
We wish to see a sign from you." He said to them in reply, "An evil and unfaithful generation seeks a sign, but no sign will be given it except the sign of Jonah the prophet. Just as Jonah was in the belly of the whale three days and three nights, so will the Son of Man be in the heart of the earth three days and three nights. At the judgment, the men of Nineveh will arise with this generation and condemn it, because they repented at the preaching of Jonah; and there is something greater than Jonah here.