Al-Anfal: (55) Indeed, the worst of living creatures...

"Indeed, the worst of living creatures in the sight of Allah"—that is, in His judgment and decree—"are those who have disbelieved"—meaning those who persist in disbelief and are firmly rooted in it. This is a commencement in explaining the states of the remaining disbelievers after having explained the states of those among them who were destroyed. He, glory be to Him, did not say "the worst of mankind," gesturing to the fact that they are removed from their company; rather, they are of the genus of beasts, and indeed the worst individuals among them.

"(So) they do not believe" — a judgment consequential to their persistence in disbelief and their rootedness in it. It is a record against them that they are of those whose hearts have been sealed, whom no deterrent can turn and no sentiment can dissuade. It is brought in the form of a parenthetical clause.

It has been said: It is a conjunction to the relative clause (the Silah), implying the meaning of a state (Hal), as if it were said: "Indeed, the worst of creatures are those who disbelieved, persisting in their lack of faith."

It has also been said: The Fa is Fasiha (eloquent/explanatory), meaning: "If you have known that those are the worst of creatures, then know that they will never believe at all, so do not tire yourself."

It has also been said: It is for conjunction, and in that is an alert that the realization of the conjuncted-upon (Ma'tuf 'alayh) necessitates the realization of the conjuncted (Ma'tuf), since this was made to follow the former as an effect follows its cause. And all of this is as you see.