on his action, how can he truly be called its agent, and how is his action based on his ability?”

I reply—and Allah is the Guide to the straight path:

Know that Allah Most High created the servant’s action as a cause that produces praiseworthy or blameworthy effects. A righteous deed—such as a prayer performed with inward and outward attentiveness, sincerity, mindfulness of Allah, and understanding of the good words and righteous deeds upon which it is founded—is immediately followed by light in his heart, ease in his breast, tranquillity in his soul, increased knowledge, firmer certainty, and greater strength of understanding. Other effects include bodily strength, radiance in his face, restraint from indecency and wrongdoing, love for him being placed in people’s hearts, protection from affliction, and further things that He knows but we do not. These effects—the light, knowledge, certainty, and so forth that he has attained—are themselves causes leading to further, higher effects, whether of the same kind or of a different kind, and so on.

Hence it has been said:

“Part of the reward for a good deed is another good deed after it, and part of the punishment for an evil deed is another evil deed after it.”

Likewise, an evil deed—lying, for example—brings immediate punishment upon its perpetrator: darkness and hardness in his heart, constriction in his breast, hypocrisy, turmoil, forgetting what he has learned, the closing of a door to knowledge he had been seeking, diminished certainty and understanding, darkness in his face, hatred for him in people’s hearts, and greater boldness in committing another sin, whether of the same kind or a different kind, and so on—unless Allah comes to his aid with His mercy.