What do the four schools say about a disbeliever who is so sick and depraved that he dares to curse his Creator, Allah? Also, what do they say about a disbeliever who curses our Prophet, sallallahu ʻalayhi wa sallam?

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, sallallahu ʻalayhi wa sallam, is His slave and Messenger.

If the mentioned cursing was committed by a sane Muslim, then he is declared an apostate without any difference of opinion among the scholars in this regard. The Muslim judge should give him respite to repent to Allah, the Exalted; otherwise, he should be killed for apostasy according to the consensus of the scholars if he is a man. If the blasphemer is a woman, the majority of the scholars held that she should be killed for apostasy as well, contrary to the Hanafis, who held that the female apostate should not be killed for apostasy; rather, she should be coerced by beating and imprisonment until she returns to Islam or dies. However, this view is outweighed given that when the Prophet, sallallahu ʻalayhi wa sallam, sent Muʻaath to Yemen, he said to him, “If a man apostatizes from Islam, call him to revert; if he does not revert, strike his neck. If a woman apostatizes from Islam, call her to revert; if she does not revert, strike her neck.”

Al-Haafith Ibn Hajar wrote, “Its chain of narration is Hasan (good); it directly addresses the subject matter, and it should be used as supportive evidence in this regard. It is further supported by the fact that both men and women are subject to the same Hudood (corporal punishments prescribed for certain crimes in the Shariah) for all the crimes such as adultery, theft, consumption of alcohol, and slander. For example, the punishment of both the married adulterer and adulteress is stoning to death.” [Fat-h Al-Baari]

He also said, “Abu Bakr, during his caliphate, killed a woman who apostatized, and none of the Companions, as many as they were at that time, objected to his action.”

If this blasphemer is a non-Muslim to begin with, then what he said is only an addition to his disbelief, except that if he resides in the Muslim state on account of a covenant of protection with Muslims, that covenant is annulled by his act of blasphemy. The author of Az-Zaad (a Hanbali book) wrote about breaching the covenant of protection between non-Muslim residents and Muslims, “If he commits an act of blasphemy against Allah, His Messenger, or His Book (the Quran), his covenant is breached, but this does not apply to his wife and children. His blood and his wealth are no longer inviolable...”

Shaykh Ibn ʻUthaymeen commented on that saying;

“His statement, ‘If he commits an act of blasphemy against Allah, His Messenger, or His Book’ should also include ‘or His Shariah’; so if he cursed Allah or said, ‘Allah is poor,’ his covenant with the Muslims is breached because he has committed an act of blasphemy against Allah. The same ruling applies if he said, ‘Allah is unjust..., Allah is ignorant and does not know.’ Making any such blasphemous statements against Allah entails the annulment of the covenant of protection between him and the Muslims... As for his statement, ‘His blood is no longer inviolable,’ it means: even if he claims to have repented; and if his covenant is annulled, he is no longer a Thimmi (disbeliever living in the Muslim lands under the protection of their ruler); rather, he becomes a belligerent disbeliever. Accordingly, the Muslim ruler is given four choices: to execute him, enslave him, release him for a ransom (money or service), or release him without ransom. The point is that he takes the ruling of a belligerent non-Muslim and not a Thimmi.”

Allah knows best.