What is the sign of Jonah in the Bible?

The sign of Jonah is a critical teaching from scripture that points to the death, burial, and resurrection of Jesus Christ. In Luke 11:30, Jesus declares that just as Jonah was a sign to the Ninevites, so will the Son of Man be to this generation. Jonah's three days in the belly of the whale foreshadowed Christ’s three days in the tomb, culminating in His resurrection which serves as the ultimate sign of God's grace and the fulfillment of His redemptive plan. The message Jonah brought to the Ninevites proclaimed salvation, mirroring the gospel message that Christ embodied. This sign underscores the necessity of believing the message of the resurrection as the core of our faith and hope for redemption.