Tafsir of Al-Anfal 8:22

"Indeed, the worst of living creatures" is a resumption of discourse presented to explain the utter wretchedness of the state of those to whom they were likened, as an exaggeration in warning and a confirmation of the prohibition following a confirmation. Ad-dawab (living creatures) is the plural of dabbah, and what is intended by it is either the linguistic or the conventional meaning; that is, the worst of those that crawl upon the earth, or the worst of beasts in the sight of Allah—that is, in His judgment and decree—are "the deaf," who do not hear the truth, "the dumb," who do not speak it. The plural form is used according to the meaning. They were described as such because the purpose for which these two senses were created was the hearing of the truth and the speaking of it; since neither of these existed in them, they became as though they were utterly devoid of them.

The deaf are mentioned before the dumb because their deafness precedes their dumbness, for silence from speaking the truth is a branch of their failure to hear it, just as speaking it is a branch of hearing it. It is also said: the precedence is because the description of them as deaf is more significant in view of what precedes and follows. Then they were described as lacking intellect in the words of the Exalted, "who do not use reason," to verify the perfection of their wretched state; for a deaf and dumb person might still possess intellect through which he understands some matters, makes others understand him, and is guided to some of his needs. But when he is also devoid of intellect, he has reached the ultimate degree of wickedness and wretchedness. Thus, it becomes clear that they are the worst of living creatures, as they have nullified that by which they are distinguished from them.