Is it sufficient for a person afflicted by obsessive doubts to ignore the promptings of his mind and consider them as mere whisperings (waswasah), if he doubts whether he has committed an act that expels him from the fold of Islam, or must he research the ruling on that act, especially if he does not know whether that act is considered among what is necessarily known in the religion or not?

You have been greatly afflicted by obsessive whispers (waswas), and your cure lies in ignoring them and not paying any attention to them. Do not dwell on the past; continue with your acts of worship, for Allah does not let the reward of those who do good go to waste, and your acts of obedience will not be in vain. Repel the devil's whispers about apostasy, for the certainty of your remaining in Islam is not removed by mere doubt. We are confident that you have not committed any acts that necessitate apostasy. Take it easy and abandon these devilish thoughts that aim to deter you from obedience and worship.