Uttering Words of Disbelief in Anger and Frustration
8-8-2022 | IslamWeb
Question:
As salamu alaikum. Suppose, if a person utters words of disbelief (like insults to Allah the almighty in anger and frustration) and later repents from it. But he did not realize or consider himself a kaafir or disbeliever. Because he has firm belief and respect to Allah the almighty in heart. What he did was an outburst he could not control. He could not even think of considering himself an apostate. He repented to Allah. It is not sure whether he recited Shahadah (testimony of faith) during his wife's iddah. But he did offer salat in this period and as we know Salah includes Shahadah and he said it from heart. He was also repentant of his actions and never repeated that. Now after few years this issue comes into the mind of his wife. He is not ready to accept that anything happened to their marriage or that he might have been a disbeliever (Allah forbid). He is very embarrassed, hurt and furious whenever that topic is brought. Given that he repented can his wife consider their marriage valid and live normally with him? Although specific re-utterance of shahadah is not sure (most probably it did not happen during iddah but Allah knows best).
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
If this man pronounced the words of disbelief and blasphemy out of anger or frustration while being unaware of what he was saying, he bears no sin for that. Allah, The Exalted, says (what means): {... And there is no blame upon you for that in which you have erred but (only for) what your hearts intended. And ever is Allah Forgiving and Merciful.} [Quran 33:5]
However, if he was aware of what he was saying, he shall be held accountable for his words. His deliberation in this regard is indicative of his indifference in this regard and this contradicts what he stated that he glorifies Allah and places his trust in Him.
Anyway, as long as this man observes the obligation of the prayer, he is legislatively declared a Muslim as stated by Muslim scholars.
Al-Buhooti 
wrote, “If such a person observes the obligation of the prayer, he is declared a Muslim. If a non-Muslim person, belonging to any of the various categories of non-Muslims living in the Muslim state, performs the prayer, he is declared a Muslim in terms of the Shareeʻah ruling. If this person passed away directly after performing the prayer, only his Muslim relatives are entitled to their prescribed shares of his estate. His body should be washed according to the Sharee'ah teachings, a funeral prayer should be held for him and he should be buried in a Muslim graveyard ...” [Ar-Rawdh Al-Murbiʻ]
His wife should disregard such satanic whisperings and live with her husband normally as if nothing had happened; their marriage bond is still intact.
It should be noted that a Muslim should evade anger to the best of his ability; it leads to many evils. This is why the Sunnah warned against it. If someone gets angry, there are certain means and ways to evade its evil consequences. Please, refer to Fatwa no. (...) in this regard.
Should a Muslim to feel frustrated at any time, he should remember Allah frequently, place his trust in Him, and rely on Him. Allah, The Exalted, says (what means):
- {Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah hearts are assured."} [Quran 13:28]
- {...And will provide for him from where he does not expect. And whoever relies upon Allah - then He is sufficient for him. Indeed, Allah will accomplish His purpose. Allah has already set for everything a (decreed) extent.} [Quran 65:3]
Allah knows best.