Matthew 12:40

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.