How does a Muslim rid himself of the whispers of Satan that drive him to disbelief and polytheism and cause him to doubt his worship?

Satan cannot snatch away faith, because the Giver and Taker is Allah. To rid yourself of Satan's delusions, follow these steps: Seek refuge in Allah with every thought, turn away from obsessive whispers and do not dwell on them, fill your time and mind with what is beneficial and useful, supplicate at all times, fortify yourself with the remembrance of Allah, and consult a specialist doctor for obsessive-compulsive disorder to combine faith-based treatment with medication.