Jonah is one of he more fantastic books in the Bible -- the other is Job -- and many have questioned its veracity. Something about a whale (which is not accurate: try fish) and being drowned. They miss the point. The biggest miracle is that Nineveh repented.
A couple of weeks ago Kea and I had to go to the biggest city in our Island. After doing what we went for, we walked for a dinner and there was a street preacher proclaiming the gospel and that unless you repent you would be destroyed. This city lost almost 200 people in an earthquake a decade ago, and it is still rebuilding.
The preacher was being ignored.
We should not do so, for if we do not repent then God will let us receive the full measure of our injustices and evil as our judgement. By the standards we proclaim we will be found wanting. And no one can argue back, and say he is unjust.
3 Then the word of the Lord came to Jonah the second time, saying, 2 “Arise, go to Nineveh, that great city, and call out against it the message that I tell you.” 3 So Jonah arose and went to Nineveh, according to the word of the Lord. Now Nineveh was an exceedingly great city, three days' journey in breadth. 4 Jonah began to go into the city, going a day's journey. And he called out, “Yet forty days, and Nineveh shall be overthrown!” 5 And the people of Nineveh believed God. They called for a fast and put on sackcloth, from the greatest of them to the least of them.
6 The word reached the king of Nineveh, and he arose from his throne, removed his robe, covered himself with sackcloth, and sat in ashes. 7 And he issued a proclamation and published through Nineveh, “By the decree of the king and his nobles: Let neither man nor beast, herd nor flock, taste anything. Let them not feed or drink water, 8 but let man and beast be covered with sackcloth, and let them call out mightily to God. Let everyone turn from his evil way and from the violence that is in his hands. 9 Who knows? God may turn and relent and turn from his fierce anger, so that we may not perish.”
10 When God saw what they did, how they turned from their evil way, God relented of the disaster that he had said he would do to them, and he did not do it.