to obey, when accompanied by ability (1), necessarily results in obedience, [for when firm resolve is accompanied by ability and a fully operative motive, it necessarily brings about the act within one’s power] (2). If obedience consists in uttering (3) the two testimonies of faith, whoever wills to do so [with firm resolve] will certainly do it [because ability and the fully operative motive are present]; whereas anyone who (4) does not do so is known not to have willed it. If, however, he (5) does not will to obey, it is impossible for him to ask the Messenger (6) for Allah to create obedience within him. For if he asked the Messenger (7) for Allah to create it within him, he would thereby will it (8). Thus, only one who wills it can conceivably say such a thing, and no one wills an act of obedience within his power (9) without performing it.

This becomes evident from the seventh line of argument: (10)

It may be said: You are capable of believing and have the power to do so. If you willed it, you would do it. You have not believed only because you do not will to—not because you are incapable of it or lack the power to do so. We have already explained that the capacity which is a condition for being commanded is present before the act in both the obedient and the disobedient, [and is present at the time of the command in the obedient person] (11), unlike the capacity exclusive to the obedient, which exists only together with the act.