The Prophet Jonah (or Jonas) lived in the 8th century before Christ. He prophesied to the Israelites and the Ninevites, calling all to repentance. He also foretold of the coming Messiah. Jonah was eaten by a sea creature and spent three days in its belly until he was vomited out. The Lord describes this as a sign of His own three-day burial and resurrection in Matthew chapter 12.
Jonah's book of prophecy, one of the Minor Prophets, is read in the Orthodox Church during the Vesperal Divine Liturgy on Great and Holy Saturday. It is one of fifteen passages that are read on that day, all of which point to the coming Resurrection of Christ.
The Prophet Jonah is commemorated on September 22.