If they repent from polytheism yet neither establish the prayer nor give the zakah, they are not our brothers; and even if they establish the prayer but withhold the zakah, they are still not our brothers.

The bond of religious brotherhood is severed only when a person leaves the faith altogether; it is not nullified by mere immorality or by a lesser form of disbelief that does not reach outright apostasy.

Have you not considered His words about homicide: “So whoever is pardoned by his brother in any respect, then let there be a fair compliance and payment to him in a good manner” (al-Baqarah: 178)? Allah here calls the deliberate killer the “brother” of the slain, even though intentional murder is among the gravest of major sins, for He also says: “Whoever kills a believer intentionally—his recompense is Hell, wherein he will remain; Allah’s anger and curse are upon him, and He has prepared for him a tremendous punishment” (an-Nisaʾ: 93).

Then reflect on His statement regarding two factions of believers who fight one another: “If two groups of the believers fight, make peace between them …” and His words, “The believers are but brothers, so make peace between your brothers” (al-Hujurat: 9-10). In these verses Allah affirms the brotherhood between the peacemaking party and the two warring factions, even though fighting a believer is an act of disbelief, as is established in the authentic hadith recorded by al-Bukhari and others from Ibn Masʿūd (may Allah be pleased with him), that the Prophet ﷺ said: “Reviling…"