Matthew 12:40
For just as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth. The sign of Jonah is the resurrection: as Jonah spent three days in the fish's belly and emerged to preach to the Ninevites, so the Son of Man will spend three days in the heart of the earth and emerge in resurrection. The comparison is the first explicit resurrection prediction in Matthew's Gospel. The sign that will be given to this generation is the greatest sign — and the generation that rejected the miracles will also reject the resurrection (Matthew 28:12–15).