Abu Dawud

Hadith Commentary:
(1)
A fundamental point to remember regarding the aforementioned verse is that if a ruling given to the Jews in the Torah is mentioned by the Qur’an in such a way that there is no mention of any amendment or abrogation, and neither did the Messenger of Allah (sallallahu alayhi wa sallam) object to it, then that ruling will be equally applicable to Muslims, even if the Qur’an does not separately state it for Muslims—just as is the case with the ruling of stoning (rajm).
(2)
The form of retribution (qisas) described in this verse is supported by hadith, as is evident in the aforementioned hadith, and the hadith regarding the Jew whose head was crushed also supports this position. From this hadith, it has also been deduced that it is permissible to kill the Khawarij and rebels, because they are those who separate themselves from the community of Muslims (jama‘at al-muslimin).
(‘Umdat al-Qari: 16/149) (3)
It should be noted that three cases of killing are mentioned in the aforementioned hadith; besides these, there are other cases in which killing is permissible, although with some effort, the remaining cases can be included within these three categories.
And Allah knows best.

Explanation:
1:
Compared to other religions, Islam has given the greatest regard to the protection of human lives, as well as their preservation and the maintenance of peace and security.
This is why, after shirk (associating partners with Allah), the killing of a soul is considered the gravest sin in Islam.
For this reason, the Wise Lawgiver has only permitted the killing of a Muslim in the presence of one of three circumstances:

(1)
An adult free person who commits adultery (zina) while being married,

(2)
Deliberately killing an innocent person unjustly and oppressively,

(3)
Apostasy from Islam, because such a person’s heart becomes so devoid of goodness that he no longer possesses the ability to accept the truth.

(1) Islam has legislated retribution (qisas), however, if the heirs of the murdered person agree to pardon, then blood money (diyah) must be paid. But this applies only in cases of intentional murder (qatl ‘amd), not in cases of accidental killing (qatl khata’). Accidental killing is when, for example, a shot is fired at an animal but suddenly a person comes forward and is hit by the bullet, or a shot is fired thinking it is an animal, but it turns out to be a human. In such a situation, retribution (qisas) will not be applied, but payment of blood money (diyah) is obligatory, because the blood of Muslims cannot be wasted.

(2) The fear of retribution (qisas) prevents the killer from committing murder, and taking retribution (qisas) also prevents unjust bloodshed. It prevents the spread of fighting.

(3) The general law of retribution (qisas) is as stated in the blessed hadith, however, if a person unjustly attacks someone with the intent to kill, and then is killed in self-defense, then retribution (qisas) will not be taken from such a person either.

Benefits and Issues:
The meaning of separating from the congregation of Muslims is that a person abandons Islam and thus exits from the fold of Muslims, adopting another religion and being counted among the disbelievers. This does not refer to any organization of Muslims that has been established for the purpose of serving the religion, propagation, or jihad, etc., and in which every Muslim can voluntarily become a member.

A Muslim, just as he is a Muslim before joining such an organization, remains a Muslim even after leaving it.

Such a Muslim also cannot be declared a rebel, because these organizations do not have the status of an Islamic state, rebellion against which carries the punishment of death.