Calvin's Take on Jonah (4:1)

Jerome commends this grief of Jonah, and compares it to the holy zeal of Paul when he wished himself to be an anathema for his brethren, (Romans 9:3) for he denies that he grieved because God had showed mercy to so illustrious a city; but because the conversion of the Gentiles was a certain presage of the destruction of the chosen people. As then Jonah perceived as in a mirror the near ruin of Israel, he on this account grieved, if we believe Jerome: but this notion is extremely frivolous; for, immediately after, God reproved Jonah and declared that he acted perversely in grieving.
Jonah shows clearly that the cause of his grief was another, even this, -- that he was unwilling to be deemed a false or a lying prophet: hence was his great grief and his bitterness. And this we see, had God not expressed his mind, was unjust and inconsistent with every reason.
We may then conclude that Jonah was influenced by false zeal when he could not with resignation bear that the city of Nineveh should have been delivered from destruction: and he also himself amplifies the greatness of his sin. He might have said, in one word, that it displeased Jonah; but not satisfied with this simple form, he adds, that he felt great displeasure or grief; and he afterwards adds, that he was very angry. Though the beginning may not have been wrong, yet excess was sinful. But he confesses that there was excess, and want of moderation in his grief: since then he accuses himself in plain words what good is it, by false and invented pretenses, to cover what we clearly see cannot be excused?