What does the Bible say about the sign of Jonah?

The sign of Jonah is a profound illustration used by Jesus in Luke 11:29-30, where He states that just as Jonah was a sign to the Ninevites, He is the ultimate sign to this generation. Jonah's three days in the belly of the fish parallel Jesus' death and resurrection, encapsulating the core message of the Gospel—that salvation is of the Lord and hinges on Christ's work as Redeemer. Jesus' statement emphasizes that He is the fulfillment of this sign, highlighting His role in the redemption of His people through His death on the cross and subsequent resurrection.