Imam Baqir [a] said: "It is compulsory for every Muslim to conceal even seventy great faults of his fellow Muslims (in order to save his prestige)." (His faults should be dealt with personally but not be spread among the members of society).
Bihar-ul-Anwar, vol. 74, p. 301
Imam Amir ul Mu'mineen Ali [a] said: "Accept the apology of your Muslim brother and if he has not any, invent one for him yourself."
Bihar-ul-Anwar, vol. 74, p. 165
Imam Amir ul Mu'mineen [a] said: "The worst form of betrayal is the disclosure of confidential information."
Mustadrak Al-Wasa'il-ush Shi'ah, vol. 12, p. 305, No.14155
Imam Amir ul Mu'mineen Ali [a] said: "Your admonition (to the wrong-doer) in the presence of people is to humiliate him." (You must talk to him in private).
Ghurar-ul-Hikam, p. 322
Imam Sadiq [a] said: "From the most beloved deeds with Allah, Almighty and Glorious, is bringing happiness to a Muslim believer such as: satiating his hunger, removing his grief, or paying his debt."
Al-Kafi, vol. 2, p. 192