SHAFAQNA – It is narrated from the Prophet of Islam (PBUH) who said: To like true believers is the biggest branch of the tree of belief. Be aware that the one whose friendship or avoidance is for the sake of God and gives or prevents for the sake of Allah (SWT), such a person is one of the chosen ones by God . It is also narrated from the Prophet (PBUH) asking his companions: Which of the handles of belief is stronger? Some replied: God and his messenger are wiser, some said: Salaat and others answered: Hajj and others mentioned Jihad. The Prophet said: There is a virtue for each one of them that you mentioned but that is not the answer. The answer is that the strongest handle of belief is friendship for the sake of God, avoidance for the sake of God, friendship with the friends of God and avoiding the enemies of Allah (SWT) .
 Osoul Kafi, Vol. 3, Page 189.
 As above, page 190.