آداب الخلاف
Abu Khirāsh Hadrad al-Aslami (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) said: “Whoever forsakes his brother for a year is like shedding his blood.”
عن أبي خِراش حَدْرَدِ بن أبي حَدْرَدٍ الأسْلَمِي -رضي الله عنه- مرفوعاً: «من هَجَر أخَاه سَنَة فهو كَسَفْكِ دَمِهِ».
شرح الحديث :
The one who abandons his brother for a year for no Shariah-approved excuse deserves punishment, just like shedding his blood . The punishment due here is a discretionary punishment, out of retribution and deterrence. Nevertheless, if there is a Shariah-approved excuse, like practicing religious innovations and immoralities, then forsaking such people must continue as long as they do not repent and return to the truth.