Allah the Exalted said:
٢٨٠ - باب تحريم الهجران بين المسلمين فوق ثلاثة أيام إلا لبدعة في المهجور، أو تظاهر بفسق أو نحو ذلك
Allah the Exalted said:
The believers are but brothers, so make settlement between your brothers. And fear Allāh that you may receive mercy.
And He the Exalted said:
O you who have believed, do not violate the rites of Allāh or [the sanctity of] the sacred month or [neglect the marking of] the sacrificial animals and garlanding [them] or [violate the safety of] those coming to the Sacred House seeking bounty from their Lord and [His] approval. But when you come out of iḥrām, then [you may] hunt. And do not let the hatred of a people for having obstructed you from al-Masjid al-Ḥarām lead you to transgress. And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allāh; indeed, Allāh is severe in penalty.
It is related from Anas (may Allah be pleased with him) who said: The Messenger of Allah ﷺ said: "Do not sever ties, do not turn your backs on one another, do not hate one another, and do not envy one another; rather be brethren, O servants of Allah. It is not lawful for a Muslim to shun his brother for more than three days." Agreed upon.
It is related from Abū Ayyūb (may Allah be pleased with him) that the Messenger of Allah ﷺ said: "It is not lawful for a Muslim to shun his brother for more than three nights: they meet, and this one turns away and that one turns away; the better of the two is the one who is first to give the greeting of peace." Agreed upon.
It is related from Abū Hurayrah (may Allah be pleased with him) who said: The Messenger of Allah ﷺ said: "Deeds are presented every Monday and Thursday, and Allah forgives every person who associates nothing with Allah, except a person between whom and his brother there is rancour; He says: Leave these two until they reconcile." Reported by Muslim.
It is related from Jābir (may Allah be pleased with him) who said: I heard the Messenger of Allah ﷺ saying: "Satan has despaired of being worshipped by those who pray in the Arabian Peninsula, but he aims at sowing discord among them." Reported by Muslim. "Sowing discord (al-taḥrīsh)" means corrupting relations, turning their hearts, and causing them to cut one another off.
It is related from Abū Hurayrah (may Allah be pleased with him) who said: The Messenger of Allah ﷺ said: "It is not lawful for a Muslim to shun his brother for more than three days; whoever shuns him for more than three days and then dies will enter the Fire." Reported by Abū Dāwūd with a chain meeting the conditions of al-Bukhārī and Muslim.
It is related from Abū Khirāsh Ḥadrad ibn Abī Ḥadrad al-Aslamī — and it is also said al-Sulamī — the Companion (may Allah be pleased with him), that he heard the Prophet ﷺ saying: "Whoever shuns his brother for a year, it is as though he had shed his blood." Reported by Abū Dāwūd with a sound chain.
It is related from Abū Hurayrah (may Allah be pleased with him) that the Messenger of Allah ﷺ said: "It is not lawful for a believer to shun a believer for more than three days. If three days pass, let him meet him and give him the greeting of peace; if he returns it, they have both shared in the reward, but if he does not return it, the latter has borne the sin, and the one who gave the greeting has come out of the shunning." Reported by Abū Dāwūd with a good chain. Abū Dāwūd said: "If the avoidance is for the sake of Allah the Exalted, then it has nothing to do with this."