Tafsir of At-Takathur 102:6

(You shall surely see Hell) is the response to a suppressed oath, through which the warning is confirmed and the threat is intensified. By it, that which they were warned of is clarified after having been kept ambiguous, as a means of magnification.

It is not permissible for this to be the response to the law (if) of abstention (al-imtina‘iyyah), because it is certain to occur, and the response to that particle cannot be so. It has been said that it is permissible, and the meaning would be: "You will soon know the recompense." Then He, glory be to Him, says: "If you knew the recompense with the knowledge of certainty now, you would surely see Hell," meaning: Hell would be perpetually in your sight, never absent from you. This is as you see.