Matthew 12:39-40

12:39 But he answered them, “An evil and adulterous generation asks for a sign, but no sign will be given to it except the sign of the prophet Jonah. 12:40 For just as Jonah was in the belly of the huge fish for three days and three nights, so the Son of Man will be in the heart of the earth for three days and three nights.

Matthew 16:4

16:4 A wicked and adulterous generation asks for a sign, but no sign will be given to it except the sign of Jonah.” Then he left them and went away.

Luke 11:29-30

The Sign of Jonah

11:29 As the crowds were increasing, Jesus began to say, “This generation is a wicked generation; it looks for a sign, but no sign will be given to it except the sign of Jonah. 11:30 For just as Jonah became a sign to the people of Nineveh, so the Son of Man will be a sign to this generation.