أُولٰئِكَ هُمُ الكَفَرَةُ الفَجَرَةُ

It is they who are the faithless, the vicious.

EXEGESIS

Fajarah (vicious) is the plural of the active participle fājir, derived from the verb fajara, meaning to violently split open or rupture. When applied to moral character, it paints an image of one who has torn through the veil of righteousness.^{‎[1]Raghib, p. 625-626, f-j-r.}
Thus, fājir is the one who commits vile sins.^{‎[2]Mizan, 20/210-211.}

EXPOSITION

The closing verse of the surah declares the reality that the surah began to explore: God knows the true nature of each individual. Those who are condemned to hell are fully deserving of it, for that is the reality of their nature as dictated by the path they chose for themselves. Hence the attributes that are emphasised here are faithlessness and wicked deeds. If the believer earns heaven through faith and good deeds, it is only natural that the one condemned to hell has earned that through the opposite qualities. They are condemned to hell then, because they are sinful in both their theoretical framework and their practical lifestyle.

Since the surah began with admonition, there is no parallel description such as this for the pious, but rather the surah closes with this stark warning.^{‎[3]See Mizan, 20/211.}

[1] Raghib, p. 625-626, f-j-r.
[2] Mizan, 20/210-211.
[3] See Mizan, 20/211.