The [conjunction] “and (wa)” in “and when (wa idhā)” indicates that the calamity is continuous, which increases its severity. And since contrarily to “whenever (kullamā),” “when (idhā)” expresses particularity and neglect [since the generalizing suffix -mā has not been added], it points to their extreme revulsion [at the darkness] and their blindness, and that it seizes them when they are lost in the instant of [light], [which affords them] an opportunity.
The ascription of “darkness falls (aẓlama)” to the lightning alludes to darkness after light being more intense, and indicates that when in their imaginations the calamity-struck [dissemblers] see the lightning [first] banishing the darkness but then filling where they are found with it, they fancy that [the light] has been extinguished, leaving only smoke behind.
“Around (lit. on, against) them (‘alayhim)” infers harm and indicates that the darkness is not imposed by chance but is a punishment for their actions. It indicates too that the terrified [dissembler] imagines the darkness to be filling the sky and is directed at him among all beings, despite his insignificance and contemptibility, and that its assaults and harm are aimed at him in particular.
The use of “they stand [up] still (qāmū)” instead of ‘they become still, stop’ (sakanū) is a sign that due to the calamity and their strenuous efforts [to combat it] they had become bent at the waist as though bowing in prayer, which is characteristic of a person who works earnestly at something, [and had straightened up when the darkness struck them].
Now for the parts of the phrase “And if Allah so willed, He could indeed take away their hearing and sight (wa-law shā’a Allāhu la-dhahaba bi-sam‘ihim wa abṣārihim):”
Being a conjunction, the “And (wa)” hints that the hand of power acts under the veil of causes and that wisdom superintends from above all causes.
“If (law)” comprises a non-analogous conditional syllogism; that is, its not having been willed is the reason (‘illa) for their [hearing and sight] not being lost; similarly, their not being lost is evidence that divine will has not caused them to be lost. It is also a sign that the conditions for their being lost have been virtually fulfilled.
“Wills (shā’a)” indicates that the only thing binding cause and effect is divine will and wish, and it is divine power that executes [the act]. Causes are merely a veil to divine dignity and grandeur so that the hand of power is not seen by the mind’s eye[, which sees only the apparent,] to be in contact with lowly things.