Abu Ja`far Muhammad b. `Ali b. al-Husayn b. Musa b. Babuwayh al-Qummi (ra) narrated to us. He said: Muhammad b. al-Hasan b. Ahmad b. al-Walid (rh) narrated to us. He said: Al-Hasan b. Matil al-Daqaq narrated ot us. He said: Ahmad b. Abi `Abdillah al-Barqi narrated to us from his father from Yunus b. `Abd al-Rahman from `Abd al-Rahman b. al-Hajjaj. He said
I heard al-Sadiq (as) say: Whoever sees his brother doing something he hates and does not turn him away from it when he is able to, then he has betrayed him. Whoever does not avoid friendship with a fool, then I suspect that he is of his character.