Faith and its cessation as a violation of the element of action, which is a condition of validity, as previously stated. But it does not lead to disbelief, rather to فسق (fasiq - unrighteousness/immorality). So, فسق is an independent degree, contrary to faith and allied with disbelief.

This is the same opinion reached by the Mu'tazila and Ibn Hazm among the theologians. The Mu'tazila held that the perpetrator of a major sin is not called a believer, contrary to what the Murji'a say. Nor is he called a disbeliever, as the Khawarij say. Rather, he is called a فاسق (fasiq). This is the "position between two positions" which they made one of their five principles. Ibn Hazm held that faith has several opposites, among them فسق, which is abandoning the performance of obligatory duties (i.e., committing major sins). This is a position other than disbelief, which is the denial of belief in the heart or confession with the tongue. Thus, the Mahdi met the Mu'tazila and Ibn Hazm in the perpetrator of a major sin, and differed from the Ash'aris, who consider that "the perpetrator of a major sin is among the people of prayer, a believer, and they say he is obedient by his faith and disobedient by his فسق."

Therefore, to clarify the aforementioned difference of opinion regarding the reality of faith and the perpetrator of a major sin, the summary of his opinion on faith is that its reality is only established by the completion of its three elements: belief, confession, and action. If one of the first two elements is absent, it is disbelief. If action is absent due to persistent commission of major sins, it is فسق. However, if it is the abandonment of prayer, it is more likely disbelief.

(See: Al-Qadi Abd al-Jabbar, Sharh al-Usul al-Khamsa: (17). See: Ibn Hazm, Al-Fasl: 3/154 onwards. However, Ibn Hazm in another place (Al-Fasl: 4/4) denies that فسق is a position other than disbelief and faith, and asserts that there are only these two positions. He tends to say that a person performs actions that are faith and is a believer according to them. And he performs actions that are فسق and is a فاسق according to them. So he is a believer from one perspective and a فاسق from another. In any case, what is established with him is that فسق is a degree in designation, even if it is not a degree in ruling. (See: Al-Iji, Al-Mawaqif: 2/458. It has been mentioned that (See: Al-Razi, Al-Muhassal: 239) the perpetrator of a major sin, according to the Mu'tazila, is not called a believer or a disbeliever. According to the majority of the Khawarij, he is a disbeliever. According to the Azariqa, he is a polytheist. According to the Zaydiyya, he is a disbeliever in blessings. According to Hasan al-Basri, he is a hypocrite. And see Al-Mawaqif: 2/458 onwards. And Al-Iji also mentions that the opinions differ on this in: Al-Maturidi, Al-Tawhid: 329 onwards.)