You are concerned over a plant which cost you no labor. Should I not be concerned over Nineveh, the great city? The repentance of the Ninevites was something that Jonah the prophet had not given much thought. After the Lord “forced” him to preach repentance to the Ninevites, Jonah did so but as a matter, of mere formality. He was convinced that the Ninevites were beyond redemption and as such he utilized the three days of his preaching to prepare the city for what was sure to come. But the Ninevites pulled a fast one on Jonah and they repented. And while God was more than pleased with the turn of events, Jonah was not. He got upset that the “show” had been cancelled. He was angry at God because God was gracious and merciful. He begged God to die.
Jonah was a man of his time (Assyria was not only an enemy of Israel, it was once of the nations that constantly harassed the tiny nation). As a member of a nation that had suffered immeasurably in the hands of other nations, Jonah would have been delighted at the prospect of Nineveh being destroyed. It was payback time. Had not the law prescribed an eye for an eye? God’s move disappointed Jonah who was not shy to let God know how he felt: Please take my life from me; for it is better for me to die than to live.
Jonah was angry that God had extended his treatment of Israel to the Ninevites ( I knew that you are a gracious God, slow to anger, rich in clemency, loathe to punish). How could God do this? In his answer, God reminded Jonah that he was the Creator and Father of the Ninevites. It pained him to see them lose their way and walk in darkness. But they were still his sons and daughters, and as a loving Father, he wanted to give them a chance to mend their ways. He did not approve of their wicked way of life, but he still cared for them from the depths of his heart ( should I not be concerned about the more than one hundred and twenty thousand persons who reside in the city?). Moreover, as the Responsorial Psalm says, it was time the nations learnt about the loving kindness of God in order to worship and glorify the name of the Lord.