What does the Bible say about Jonah and its significance?

The narrative of Jonah is significant in that it serves as a type, or foreshadowing, of the Lord Jesus Christ. Jesus explicitly noted in Luke 11:30 that Jonah was a sign to the Ninevites, just as He is a sign to this generation. Jonah's experience in the belly of the great fish for three days and nights symbolizes Christ's death, burial, and resurrection. Ultimately, Jonah was sent by God to preach repentance to the wicked city of Nineveh, mirroring Christ's mission to call sinners to repentance for the kingdom of God is at hand. This typology illustrates that even in the Old Testament, God's plan for redemption through Christ was being foreshadowed.