"And whenever a Surah is revealed..."
This is an explanation of their states upon its revelation while they were in the assembly where the revelation was being conveyed, just as the former [verse] was an explanation of their sayings while they were absent from it.
"(They look at one another)" to conspire to flee, detesting the hearing of it, saying—as an allusion—"(Does anyone see you?)" meaning, does any of the Muslims see you if you stand up from the assembly? Or they would wink at one another out of denial and mockery of it, saying, "Does anyone see you?" so that they might depart, revealing that they could not endure listening to it, and laughter would overcome them, so they would be exposed. On this view, "the Surah" is general. It is also said: that their looking at one another and winking was out of rage due to what the Surah contained of their disgraces and the explanation of their vile acts. Thus, "the Surah" refers to a Surah containing that. The general meaning is the most apparent.
Regardless of the interpretation, a verb of saying must be implied before the interrogative for the speech to be connected. If it is implied as a noun [verbal noun], it is in the accusative state as a circumstantial qualifier (hal), as we indicated. If it is implied as a verb, the sentence is also in the place of a circumstantial qualifier, and it is permissible to consider it a new sentence. The use of the second-person pronoun is to urge those addressed to be resolute, for a person is more concerned with his own affair than with the affair of his companions, as in His saying, the Most High: "And let him be subtle and let no one be aware of you."
"(Then they turn away)" is conjoined to "they look at one another." The sequence (thumma) here implies the existence of an opportunity and the verification that none of the believers were observing them. This means: then they all turned away from the assembly of revelation because they could not bear to hear it, due to the intensity of their hatred, or for fear of scandal through an outburst of laughter, or that their winking would be observed; or they turned away from the assembly out of rage. It is said that the intent is their turning away from guidance; the first [interpretation] is more manifest.
"(Allah has turned their hearts)" away from faith, according to their turning away from that assembly. The sentence may be an indicative statement or an imprecation. Abu Muslim and others from the Mu'tazila chose the latter. His, the Glorified's, imprecation against His servants is a warning to them and an announcement of the impending punishment upon them.
His saying, the Glorified: "(Because)"—it is said that this is linked to "turned" according to the first possibility, and to "turned away" according to the second. The letter ba indicates causality; that is, because they are a people who do not understand, due to their poor comprehension or lack of reflection, for they are either fools or heedless.