What is the ruling on Satan's whispers to a Muslim concerning matters of creed and religion, and do these whispers affect the validity of his Islam and Allah's satisfaction with him?

There is only one cure for obsessive whispering (waswasah): ignoring it and not paying attention to it, occupying oneself with beneficial knowledge and righteous deeds, supplicating to Allah, and relying on Him. For Satan has no authority over those who believe and rely on their Lord. Furthermore, sensing the danger of waswasah indicates faith, as the Prophet, peace and blessings be upon him, said to those who experienced it within themselves: "That is pure faith." Waswasah is a sign of pure faith because Satan whispers to those whom he despairs of misleading, whereas for the disbeliever, he comes from wherever he pleases. Chest tightness is one of the effects of waswasah. Among the greatest things that bring tranquility is the remembrance of Allah Almighty. Consulting trustworthy, specialized doctors is also one of the means of treating waswasah.