A--- This includes all deeds of disobedience the Legislator called "Kufr" disbelief, though the doer is still regarded as Muslim. This is such as the saying of Prophet Muhammad (Peace be upon him) that reads: "Do not return to disbelief after me (my death) by striking the necks of one another." (Bukhari and Muslim)

His (Peace be upon him) saying, "Abusing a Muslim is an outrage and fighting against him is disbelief " (Bukhari and Muslim)

Thus, the Prophet (Peace be upon him) called the fighting of Muslims one against the other "Disbelief" and the doers of this as "Disbelievers", while the Glorious Qur'an says: {And if two parties or groups among the believers fall to fighting, then make peace between them both.

But if one of them outrages against the other, then fight you (all)

against the one that which outrages till it complies with the Command of Allah. Then if it complies, then make reconciliation between them justly, and be equitable. Verily! Allah loves those who are the equitable. The believers are nothing else than brothers (in Islamic religion). So make reconciliation between your brothers, and fear Allah, that you may receive mercy}. ()