Should not I pity Nineveh...

Jonah 4: 9-11 But God said to Jonah, “Do you do well to be angry for the plant?” And he said, “Yes, I do well to be angry, angry enough to die.” And the Lord said, “You pity the plant, for which you did not labor, nor did you make it grow, which came into being in a night and perished in a night.  And should not I pity Nineveh, that great city, in which there are more than 120,000 persons who do not know their right hand from their left, and also much cattle?”

Douglas Stuart noted in NBC: 

Jonah (and the reader) must learn about the relative value of human life. Jonah, in his heat prostration, was furious at the death of his plant. Not stupid, Jonah surely had realized that God was behind these events. But he still protested in his anger that he wanted to die. The prophet who had recently eloquently thanked God for rescuing him from death now wanted to die! And it was over nothing more than a plant that had lived only briefly!

    If Jonah could care so deeply about a vine, and desire so strongly that it should not die, could not God care all the more about people—or even animals? Since all cultures value animals above plants and people above animals, God’s point to Jonah is clear. Jonah had wanted a plant to be spared, but not people. His values were completely amiss.

    Implicitly the readers are asked: Are we like Jonah? Are our values also distorted? Do we hate our enemies and wish—or pray—ill for them while accepting forgiveness and grace for ourselves? Jesus taught that his followers must love their enemies (Mt. 5:44). It is a teaching often hard to bear, but a teaching that cannot be disobeyed