Q 8: What is the ruling on boycotting a person who commits a crime, especially if they are relatives?
A: This issue requires explanation; if the criminal insists on committing the Munkar (that which is unacceptable or disapproved of by Islamic law and Muslims of sound intellect) and does not accept advice, it is permissible for relatives or neighbors to boycott them, decline their invitations, and refrain from greeting them until they perform Tawbah (repentance to Allah).
That is what the Prophet (peace be upon him) and the Sahabah (Companions of the Prophet) did with Ka`b ibn Malik and his two companions who refrained from joining the Battle of Tabuk without an excuse. The Prophet (peace be upon him) asked the people to boycott them,
so they were boycotted until they performed Tawbah and Allah accepted it. However, if boycotting a person might lead to greater harm such as being an influential person in the country, he should not be boycotted; he should rather be treated kindly so that boycotting him does not lead to a greater evil than his crime. The evidence for this is that the Prophet (peace be upon him) did not treat the chief of the hypocrites, `Abdullah ibn Ubayy ibn Salul, the same way he treated Ka`b and his two companions, but he treated him nicely, being the chief of his tribe. If he had boycotted or imprisoned him, this might have led to Fitnah (trial) among his followers in Madinah. That is why the Prophet (peace be upon him) treated him kindly until he died while still a hypocrite. May Allah grant us safety!
There are other accounts of some people whom the Messenger of Allah (peace be upon him) did not boycott but treated them nicely until they were guided by Allah. Mildness in Da`wah (calling to Islam) is one of its most necessary requirements. May Allah grant us success!