Ibn Majah

1؎ : The noble instruction: "He is not one of us" contains a severe warning for the person who raises a weapon against a Muslim, meaning that in his morals and habits he has become like the disbelievers of the Age of Ignorance, who were accustomed to fighting and waging war among themselves. Regarding those hadiths in which the Messenger of Allah (sallallahu alayhi wa sallam) declares disassociation from the one who commits a major sin (kabirah), the views of the scholars of Islam are as follows:

1- The meaning of the Messenger of Allah's (sallallahu alayhi wa sallam) declaration of disassociation from the perpetrator of a major sin is that such a person is not a follower of your obedience and example, nor is he a protector and adherent of Islamic law. Thus, in those hadiths in which the Prophet (sallallahu alayhi wa sallam) said regarding the perpetrator of minor sins «ليس منا» ("The one who does such-and-such is not one of us"), the negation of faith therein refers to such a necessary and essential faith by which a person becomes deserving of reward and recompense without punishment or retribution. And this meaning is similar to the interpretation of the negation of previous faith. This is the view of Abu Ubayd al-Qasim ibn Sallam and Shaykh al-Islam Ibn Taymiyyah.

2- From Imam Sufyan ibn ‘Uyaynah, its meaning is transmitted as follows: «ليس مثلنا» "That is, he is not like us."