Imam Sadiq (peace be upon him): Then Allah mentioned those to whom, after Himself and after His Messenger (peace be upon him and his family), He has given permission in His Book to call [others] to Him, and said: Let there be from among you a group who call to good, and enjoin what is right and forbid what is wrong (Al Imran/104) ... Then He mentioned the followers of His Prophet (peace be upon him and his family) and the followers of this group whom He has described in His Book by enjoining what is right and forbidding what is wrong, and made them callers to Himself and gave them permission to call [others] to Him, and said: یا أَیُّهَا النَّبِیُّ حَسْبُکَ اللهُ وَ مَنِ اتَّبَعَکَ مِنَ الْمؤْمِنِینَ [O Prophet! Allah is sufficient for you and (for) such of the believers as follow you]; then He described the believers who are the followers of His Prophet (peace be upon him and his family) thus: Muhammad is the Messenger of Allah, and those with him are stern against the disbelievers, merciful among themselves. You see them bowing and prostrating, seeking bounty from Allah and (His) good pleasure. Their marks are on their faces from the effect of prostration. That is their description in the Torah, and their description in the Injil (Al Fath/29).