[Q]: All praise be to Allāh, I am a person who performs ṣalāh and nawāfil (supererogatory prayers). Sometimes I feel myself plagued by doubts that my actions are unaccepted. This is the result of the whisperings of Shayṭān—I seek refuge in Allāh from him. What is the cure for this, may Allāh reward you?

[A]: There should be no doubt that these thoughts are from Shayṭān. A person who performs what is obligatory upon him should think positively concerning his Lord and strive to have sincerity in his actions and truthfulness in its performance. Let him leave these whisperings that attempt to persuade him that he is showing off or that he is such-and-such or such-and-such. As long as he knows that his actions are for Allāh and that he—all praise be to Allāh—is not attempting to show off for the people. For he only engages in such acts for the sake of Allāh while knowing that these thoughts are from Shayṭān. It is obligatory that he consistently seeks refuge in Allāh from Shayṭān. Furthermore, let him busy himself away from these thoughts that plague him, and object to them when they appear. Indeed, they are all from the enemy of Allāh (Shayṭān), with the goal of preventing him from his actions. Thus, combat and fight the enemy of Allāh by saying: “I seek refuge in Allāh from the accursed Shayṭān.” Then, busy yourself with other actions that cause you to forget this matter entirely like engage in the recitation of the Qurʾān, seeking forgiveness, speaking to your brothers and the people of your household and other than this from matters that turn your attention away from these whisperings.

Source: Al-ʿIlāj wa-al-Ruqá: 54-55
Translated by: Riyāḍ al-Kanadī