The Mahdi defined repentance as returning from disobedience to obedience. So, whoever returns from sin to obedience is a repentant person in Sharia. The most important thing that draws attention in the Mahdi's opinion on repentance is that he considers repentance to be valid only if it is a complete abandonment of all sins. As for the one who persists in one sin, he has no repentance, even if he abandons all other sins. This is contrary to what most theologians, of various sects, have held, as Al-Razi stated: "The majority said: Repentance from some sins while persisting in others is valid." Ibn Hazm mentioned that Al-Haba'i [Abu Hashim] Al-Mu'tazili and Muhammad bin Al-Tayyib Al-Baqillani, among all the scholars, held that whoever has sins, his repentance from any of them is not accepted until he repents from all of them. And a group followed them in this. Among those who followed him in this is Qadi Abd al-Jabbar, who says: "As for our Sheikh Abu Hashim, he held that repentance from some abominations is not valid while persisting in others. And this is the correct view among the doctrines." This strictness from the Mahdi regarding repentance might have been intended to be a deterrent to avoid all sins when the soul sometimes turns to righteousness and on the occasion of some sins, so its readiness to avoid some leads to avoiding all, given the knowledge that the reality of repentance is avoiding all. This strictness indicates the great attention and high status that the Mahdi gives to the practical and behavioral aspect of a Muslim's life, a status that is highlighted by his making the element of action an element of the reality of faith, which is invalidated by its invalidation. And his making the one who commits a major sin (the perpetrator of a major sin) as falling into wickedness, devoid of faith.