Be careful not to harm fellow believers even if they are on wrong path .

This hadith is about how Allah revealed a verse in the Quran to protect Muslims from killing each other. It was narrated by Abu Al-Aswad, who was part of an army unit being recruited from Medina. He met 'Ikrima and informed him about it, and 'Ikrima discouraged him strongly because Ibn 'Abbas told him that some Muslims were with the pagans to increase their number against Allah's Messenger, so arrows or swords could hit one of them and kill them. So Allah revealed this verse as a protection for those who are wronging themselves by staying among disbelievers. The lesson here is that we should always be careful not to harm our fellow believers even if they are on the wrong path, as only God can judge them for their actions.