a great fish. The species of whale or fish that swallowed Jonah cannot be identified with certainty. Suggestions have included the sperm whale or a large shark. The fish was God’s instrument to rescue Jonah from the depths of the sea (“the belly of Sheol,” 2:2).
three days and three nights. Jesus referred to the Book of Jonah in order to communicate truths regarding His own message and mission (Matt. 12:38–41; 16:4; Luke 11:29–32). He speaks of the “sign of the prophet Jonah” not only with reference to the three days and three nights that Jonah was in the fish (Matt. 12:39, 40), but also with regard to the efficacy of Jonah’s preaching. Without benefit of a miraculous sign, the Ninevites recognized Jonah’s message as one with divine authority, and they responded in repentance.