Jamieson, Fausset and Brown on Jonah 1:12

12. cast me ... into the sea--Herein Jonah is a type of Messiah, the one man who offered Himself to die, in order to allay the stormy flood of God's wrath (compare Psa 69:1, 2, as to Messiah), which otherwise must have engulfed all other men. So Caiaphas by the Spirit declared it expedient that one man should die, and that the whole nation should not perish (Joh 11:50). Jonah also herein is a specimen of true repentance, which leads the penitent to "accept the punishment of his iniquity" (Le 26:41, 43), and to be more indignant at his sin than at his suffering.