The success and prosperity of wicked people often raise questions about divine providence and justice. A foolish person might look at the world and mistakenly conclude that there is no ultimate justice or judge. However, the flourishing of those who do evil is merely a temporary illusion designed for their complete downfall.
The primary approach among commentators is that comparing the wicked to grass highlights the exact nature of their success. Grass grows easily, spreads rapidly, and springs up everywhere without defined limits. Yet, it dries up and withers just as quickly. This stands in sharp contrast to the righteous, who are instead compared to strong, deeply rooted trees like the cedar and the palm [רד״ק, מאירי, ביאור שטיינזלץ]. This rapid growth can also be compared to watering a field full of weeds. The purpose of bringing the weeds to the surface is not to sustain them, but to make it possible to plow the field and pull them up by the roots, ensuring they never return [ביאור שטיינזלץ].
Within this rapid growth, there are fine distinctions regarding the types of sinners and the stages of their success. One perspective differentiates between those who sin against God and those who commit crimes against other people. While those who sin against God may reach a stage of full bloom, those who harm others are cut down at a much earlier stage of sprouting. This early intervention prevents them from causing further harm to society [מלבי״ם]. Another approach views these different stages of growth as representing different areas of life. The rapid spread of grass symbolizes the accumulation of material wealth, while the initial sprouting represents success in having children [אלשיך].
Ultimately, the entire purpose of this temporary prosperity is to lead to their eternal destruction. Commentators agree that God grants wicked individuals an illusion of success in this world as payment for the few good deeds they may have performed. By rewarding them fully in the present life, God clears their account of any merit. As a result, they lose their portion in the World to Come and are condemned to eternal ruin [רש״י, אבן עזרא, מצודת דוד, מאירי, אלשיך].