What is the effect of minor sins and recommended acts upon the Khawarij, the Mu'tazila, and the Murji'ah, given their assertion that faith neither increases nor decreases?

The effect of recommended acts [mustahabbat] is limited to increasing reward and elevating rank, while the effect of minor sins is the lowering of ranks. The Murji'ah do not see any effect of minor or major sins on faith, while the Khawarij and Mu'tazilah differ in their effect based on their definition of faith.

Some Mu'tazilah believe that faith includes obligatory and supererogatory acts of obedience and avoiding major sins, while some believe it includes only obligatory acts along with avoiding major sins.

The Khawarij consider faith to be an indivisible whole; if a part of it goes, all of it goes.

The Murji'ah believe that deeds are not a pillar of faith, and that faith neither increases nor decreases, and that the perpetrator of a major sin will enter Paradise without punishment.

The Khawarij and Mu'tazilah agree with the Ahl al-Sunnah that faith includes deeds, sayings, and beliefs, but they believe that it cannot be compartmentalized, so a failure in deeds or committing major sins exits one from faith.

The Khawarij and Mu'tazilah believe that faith neither increases nor decreases; it either exists completely or disappears completely. They interpret texts that indicate the increase of faith as an increase in divine grace, evidence, or reward.

Shaykh al-Islam Ibn Taymiyyah believes that the sects of the people of desires (Khawarij, Mu'tazilah, Jahmiyyah, Murji'ah) say that faith and hypocrisy cannot coexist in a servant, and this is an error, for Allah may punish a Muslim with Hellfire and then admit him into Paradise.