Matthew 12:39-40 AMPC
But He replied to them, An evil and adulterous generation (a generation morally unfaithful to God) seeks and demands a sign; but no sign shall be given to it except the sign of the prophet Jonah.
For even 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. [Jonah 1:17.]
AMPC: Amplified Bible, Classic Edition