a. The central message of Jonah is one of "grace as unmerited favor". No individual or nation has the right to expect God to forgive his disobedience.
b. Israel had no monopoly on God's mercy, nor could it presume to limit God's forgiveness as Jonah tried to do.
c. Jonah himself had no right to expect God to send a fish to save him from the consequences of his own disobedience. Jonah's blindspot in regard to Nineveh was to begrudge others the experience of the same mercy of God that spared his own life.
d. By the close of the book, though he fulfilled God's mission, Jonah never came to any awareness that he and the Ninevites were in the exact same boat concerning disobedience and susceptibility to the judgment of God.
e. Paul in the New Testament expresses a principle related to the message of Jonah:
"For God has consigned all men to disobedience, that he may have mercy upon all" (Rom 11:32 RSV).
f. Jonah was a precursor of the grace of God extended to the Gentiles -- a theme both of other prophets after Jonah, and especially of the New Covenant.