It is narrated from Hazrat Zaid bin Thabit (may Allah be pleased with him) that when the Holy Prophet (peace and blessings be upon him) set out for the Battle of Uhud, some people from the army turned back on the way. The noble Companions (may Allah be pleased with them) became divided into two groups regarding them: one group was of the opinion that they should be killed, and the second group said no. Upon this, the following verse was revealed: "What is the matter with you that you have become two groups concerning the hypocrites?" And the Holy Prophet (peace and blessings be upon him) said: "Medina is pure; it expels filth just as fire removes the impurities of silver."