Mishkat al-Masabih

Hadith Authentication
It is Hasan (good).
The chain of this narration is weak due to Khalid bin Wahban being of unknown status (majhul al-hal).
Hafiz Ibn Hibban mentioned the aforementioned Khalid in Kitab al-Thiqat [207/4] and said:
“He was the maternal cousin of Abu Dharr al-Ghifari, and people have narrated from him.”
Al-Hakim declared him to be a well-known Tabi‘i (follower of the Companions), i.e., a famous Tabi‘i.
It is narrated from Sayyiduna al-Harith al-Ash‘ari radi Allahu anhu that the Messenger of Allah sallallahu alayhi wa sallam said:
«فانه من فارق الجماعة قيد شبر فقد خلع ربقة الاسلام من عنقه الا ان يرجع»
“Indeed, whoever distances himself from the congregation by even a handspan has cast off the collar of Islam from his neck, unless he repents, i.e., returns.” [سنن الترمذي : 2863 وقال : هذا حديث حسن صحيح غريب وسنده صحيح، الشريعة للآجري 287/1ح 7 وسنده صحيح، دوسرا نسخه ص 8]
With this supporting narration, the above hadith is also Hasan (good).

Benefit:
The hadith narrated by Khalid bin Wahban is present in the book [السنة لابن ابي عاصم 1053] with the wording «من فاروق الجماعة والاسلام فقه خلع ربقة الاسلام من عنقه» (“Whoever separates from Islam and the congregation has cast off the collar of Islam from his neck.”).

Fiqh of the Hadith:
➊ Consensus (ijma‘) in Shari‘ah is a binding proof.
➋ It is not permissible to rebel against the caliph and Muslim rulers; rather, it is a major sin, except if both parties or one party falls into an ijtihadi (scholarly) error, then they are excused.
➌ Every kind of interpretation, explanation, or reasoning that goes against the unanimous understanding of the righteous predecessors (salaf salihin) is rejected.
➍ One should always be diligent in establishing prayer in congregation.
➎ There are four fundamental causes of misguidance in the Ummah of Response (ummah ijabah):
First:
Denial of the Qur’an, hadith, and consensus (such as the takfiri Khawarij, Mu‘tazilah, and deniers of hadith, etc.)
Second:
Fleeing from the unanimous understanding of the righteous predecessors (such as the Jahmiyyah, Murji’ah, Rawafid, and Qadariyyah, etc.)
Third:
Love for false interpretations and rejected narrations (such is the practice of all groups of people of innovation and people of shirk)
Fourth:
Being in opposition to the scholars of truth and the people of truth (such as the takfiri and tanfiri Khawarij, etc.)
➏ The necessary implication of the Shari‘ah texts is that there should always be unity among Muslims.
➐ It is established from verse 9 of Surah al-Hujurat that a rebel (baghi) does not become a disbeliever due to rebellion, but rather remains among the believers; therefore, to declare someone a disbeliever (takfir) solely on the basis of evidences of threat and severity, while ignoring other Shari‘ah texts, is invalid.

Benefit:
Takfiri refers to those who declare rightly-guided Muslims to be disbelievers, and tanfiri refers to those who insult and disparage rightly-guided Muslim scholars.

Benefits and Issues:
By "the group" (jama‘ah) is meant Ahl al-Sunnah wa’l-Jama‘ah, who consider the creed of monotheism (tawhid) and adherence to the Sunnah as the foundation of the religion, and are united and in agreement upon this.

2: If a sin or mistake is committed by the Muslim ruler, it is not permissible to rebel against him, except if he commits clear disbelief (kufr) or when he deviates from the path of implementing the religion.