The real focus of the four short chapters is the dialogue between God and Jonah. God begins the conversation with Jonah, who's a well known prophet in Israel. He tells him to go to Nineveh, a great city in Assyria and tell them that God's judgment is coming. Now the Assyrians were Israel's archenemies, despised and hated by any self-respecting Israelite. There was a reason for this. The Assyrians were unspeakably cruel and wicked. Israel had been captured, plundered, and massacred by these people. Judgment for the Assyrians was probably music to the prophet's ears.
If you read the first chapter of Jonah, you won't find that Jonah says anything about this assignment. Instead, he acted out in a passive aggressive manner and ran away. His actions spoke louder than any words.
But Jonah ran away from the L and headed for Tarshish. He went down to Joppa, where he found a ship bound for that port. After paying the fare, he went aboard and sailed for Tarshish to flee from the L. Jonah 1:3 NIV
I'm so glad our God gives second chances, and sometimes many more. Even when we deliberately run away from what He wants us to do. Even when we deserve His harshest judgment, He acts in mercy and grace. Another prophet--Jeremiah had this to say:
Because of the Lord's great love we are not consumed, for his compassions never fail. They are new every morning; great is your faithfulness. Lamentations 3:22-23 NIV