Thought from Today's Old Testament Passage:
The book of Jonah has often been challenged as to its credibility and historical value because of the amazing adventures it narrates concerning the prophet from Gath-hepher. How could a man be saved from drowning by the friendly offices of a whale (or "large fish"), who kept him safely in his stomach for three days and then ejected him safely onto the shore?
According to Matthew 12:40, Jesus the Son of God believed that Jonah was completely historical. He showed this by stating, "For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth" (NIV). This puts the issue on a very clear footing. Jesus here affirms that Jonah's experience in the belly of the whale was a type of the death burial, and resurrection that awaited Him between Good Friday and Easter morning. The coming experience of Christ, which certainly was historical, would serve as an antitype to the experience of the prophet Jonah. If the antitype was historical, then the type must also have been historical. No fictional past episode can serve as a prophetic type of a future literal fulfillment. Only fiction can correspond to fiction; only fact can correspond to fact.
Gleason L. Archer, Encyclopedia of Bible Difficulties (Zondervan, 1982), pp. 301-302