God confronts Jonah with a sharp moral and logical argument, exposing the vast gap between human attachment driven by self-interest and divine mercy for creation. The comparison is built on a logical progression from a minor, insignificant event to a major reality. Jonah feels genuine sadness and compassion over the loss of a plant [מצודת ציון]. However, the primary approach among commentators is that Jonah did not pity the plant because of its own intrinsic value. Instead, his feelings stemmed entirely from his personal need for the shade it provided and his sadness over losing that comfort [מלבי״ם, רד״ק, אברבנאל]. He enjoyed the plant much like a son taking shelter under the protective care of his father [אברבנאל].
To highlight the lack of reason in Jonah's sorrow, God points out that Jonah invested no effort into the plant. Naturally, a person feels deeper sadness over losing something they worked hard to cultivate through plowing, sowing, watering, and fertilizing [רש״י, מצודת דוד, רד״ק]. Jonah did none of these things. The argument naturally follows: if Jonah felt such pity for an object he did not even create, surely God should have mercy on His own creatures, the work of His hands. While God does not physically labor to create the world, the text uses human terms to make the concept understandable [רד״ק, אבן עזרא].
The motives behind these two types of pity are completely different. Jonah was driven by pure personal benefit. In contrast, God is motivated to spare His creations because human beings reflect His honor in the world, and He loves them just as a father loves his children [רד״ק, אברבנאל].
Furthermore, the plant itself lacked any real importance or stability. Its entire lifespan was essentially a single night [מצודת ציון, רד״ק, אבן עזרא]. The commentators agree on its brief timeline: it grew over the course of one night, provided shade for Jonah the following day, and by evening began to wither. By the dawn of the second night, it was struck by a worm and completely destroyed [אבן עזרא, רד״ק, מצודת דוד]. It was a fading, empty thing whose rapid appearance and disappearance left no meaningful mark on the world [מלבי״ם, ביאור שטיינזלץ, אברבנאל].
The contrast is absolute. It is illogical to mourn a temporary, worthless plant that simply appeared and vanished with such speed [מצודת דוד]. Against this backdrop, it becomes entirely clear why God must have mercy on a massive city like Nineveh, filled with tens of thousands of human beings who are the direct work of His hands.