Tafsir of An-Naba' 78:4

( Kalla ) is a deterrent against the questioning, according to both interpretations previously mentioned regarding it. It has been said that it is a deterrent against the questioning itself, and against the disagreement—meaning the opposition to the Messenger (may Allah bless him and grant him peace) regarding the matter of the Resurrection. This is countered by the argument that the sentence containing it was not intended for its own sake, so it is unlikely that the deterrence pertains to what is within it.

His, the Almighty’s, saying ( saya'lamun )—"they will soon know"—is a threat to those questioners and mockers, presented by way of an isti'naf (resumptive sentence) and as a justification for the deterrence. The sin (in sa-ya'lamun) indicates proximity and emphasis. The object of the verb "to know" is omitted; it refers to the various types of calamities and punishments they will encounter. It is expressed as "knowing" (rather than "suffering") because it occurred in the context of questioning. The meaning is: let them be deterred from what they are upon, for they will soon know the reality of the situation when punishment and retribution befall them. Estimating the object in this manner is a consequence of the questioning.

It is said that the object is what the apparent wording suggests, which is the occurrence of that which they are questioning; meaning they will know that, and thus they will be shamed for their questioning and mockery before their Lord, the Mighty and Majestic. The evident truth is that what has been mentioned is a threat.

Whoever considers the pronoun in "they question" ( yatasa'alun ) to refer to people in general holds that this is a case of taghlib (predominance), for it refers to those who are not believers and certain of it. Some have permitted that Kalla saya'lamun be both a deterrence and a promise (encouragement) to be deterred; the meaning being: let them be deterred, for they shall soon know the rewards of such deterrence. You know that this is common in threats, and it is the most readily understood meaning in such contexts. And His saying, the Exalted...