And this does not preclude their being able to hear once the covering over their hearts, hearing, and sight is removed. Their failure to hear is due to the quality from which their designation is derived—namely, disbelief. As long as this remains their condition, they remain as described. Yet their condition can change, as He says:

“Unless Allah wills.”

And this is what actually happens.

Such statements teach a person not to suppose that his calling, warning, and explanation will necessarily bring about guidance, even if he is the most accomplished of people. Although the caller may be righteous, sincere in his counsel, and pure in his intentions, the person he calls may not respond—not because of any deficiency in the call, but because of corruption in its recipient. This is because achieving the desired result depends both on the agent’s action and on the recipient’s receptiveness. A sharp sword, for example, has an effect only if the material it strikes is susceptible to it; it does not cut stone, iron, and the like. Blowing has an effect when there is something receptive to it; it has no effect on ashes.

Calling, teaching, giving guidance, and everything of this kind involve an agent—the speaker who conveys knowledge, guidance, and warning—and a recipient, who is the listener. If the listener is receptive, the warning, instruction, and guidance take full effect. If he is not receptive, one says: “I taught him, but he did not learn; I guided him, but he did not follow the guidance; I addressed him, but he did not listen attentively,” and so forth.