The order and positioning of the parts of the phrases:
Consider this: the definiteness expressed by “when (idhā)” in “When it is said to them: ‘Do not spread corruption on the earth’ (Wa idhā qīla la-hum lā tufsidū fi’l-arḍ)” denotes the necessary obligation of ‘forbidding what is unlawful.’
The passive form of “it is said (qīla)” indicates that such prohibition is incumbent on all (farḍ kifāya ‘alā al-umūm).
In the “la-” of “la-hum –to them” is a sign that the prohibition must be in the form of advice, not coercion; and through persuasion rather than by force.
“Do not spread corruption (lā tufsidū)” is a summary in the form of a conditional syllogism; that is, “do not do that, for it will lead to anarchy. Relations [requiring] obedience will be severed, justice and its system will be thrown into disorder, the bonds of unity will be broken, and this will lead to corruption. So don’t do that lest you cause corruption.”
The phrase “on the earth (fi’l-arḍ)” corroborates and perpetuates the prohibition, for [its effect] is temporary. The admonition therefore has to fix it permanently in the brain of the one addressed by appointing his conscience to always restrain him from beneath. This is either by exciting his vein of fellow-feeling, or by arousing his desire to flee from public disgust. “On the earth (fi’l-arḍ)” arouses these two veins, for the phrase addresses [the dissemblers] saying: “This depravity of yours spreads through mankind. Why do you feel such hatred and anger at all the people, some of whom are innocent, or poor, or unknown by you? Why don’t you feel sorry for them and pity them? We can see you have no sympathy for your fellow men, but at least you should realize that this action of yours attracts their loathing.”
• If you were to ask: Which of [the dissemblers’] objectives looks to the people at large? How can their depravity spread to everyone?
You would be told: Just as everything appears dark and ugly to a person who looks through a dark lens, so everything appears hateful and odious to the person whose sight is veiled by dissembling and whose heart is corrupted by unbelief. His heart is full of malice towards all men, indeed, all beings, and he stubbornly opposes them. Furthermore, if one tooth of a fly-wheel in the workings of a clock is damaged, the clock is affected either wholly or partially. Similarly, mankind’s order is affected by one person’s dissembling, for it is set in order through justice, Islam, and obedience. Alas! [The dissemblers’] continuously scattered poisons have accumulated and resulted in the present ignominy.