then Allah’s proof would have been nullified, for no single person other than the Messenger could undertake this task, since none but he is infallible.

Whoever reflects upon these and other matters will know that what Allah chose for Muhammad [—may Allah bless him and grant him peace—] (1) and his Ummah is the most perfect of all arrangements.

A tenth answer is as follows:

It is impossible for explicit texts to cover every particular case, whereas universal principles have already been expressly laid down [in such texts] (2). Thus, if he had explicitly designated a particular person and commanded that he be obeyed in determining the universal principles, this would have been invalid. If he had commanded that person to be obeyed in particular cases, whether those cases conformed to the universal principles or contradicted them, this too would have been invalid. And if he had commanded that person to be obeyed in particular cases only when they conformed to the universal principles, then this is the rule governing every person vested with authority.

Moreover, had he explicitly designated a particular person, some might suppose that whoever assumed authority after him, if not likewise designated, could not rightfully be obeyed, since obedience to the first had become obligatory only through explicit designation, whereas no such designation existed for the second.

If it is said, “Each one would explicitly designate the next,” this could only be the case if the second person were infallible. Yet infallibility belongs to none but the Messenger. This demonstrates that the doctrine of explicit designation presupposes the doctrine of infallibility, and that is among the most corrupt of doctrines.

The same applies to this—namely, the explicit designation claimed by the Rāfidah (3): the command to obey the one vested with authority in everything he says, without referring what he says back to the Book and the Sunnah when it is disputed.