The Rights of Fellow Muslims
The Holy Prophet (S) said: "He who grieves a true Muslim cannot then compensate for it by offering him the entire world because it is not sufficient compensation (unless he repents and appeases the said person)."
Bihar-ul-Anwar, vol. 75, p. 150
Imam al-Kadhim (‘a) said: "Among your most compulsory duties towards your Muslim brother is that you conceal nothing from him which profits him either in this life or in the Hereafter."
Bihar-ul-Anwar, vol. 2, p. 75
Imam Hasan, the second Imam (‘a), said: "Treat others similar to the way you would like for them to treat you."
Bihar-ul-Anwar, vol. 78, p. 116
Imam Amir ul Mu'mineen ‘Ali (‘a) said: "May Allah have mercy upon the person who services a right and removes a wrong, or refutes an injustice and establishes justice."
Ghurar-ul-Hikam, p. 181
Imam as-Sadiq (‘a) said: "These four characteristics are from the manners of Prophets (‘a): righteousness, graciousness, patience and perseverance in tolerating misfortunes, and rising for the right of a believer."
Tuhaf-ul-Uqul, p. 277
Imam Amir-ul-Mu'mineen ‘Ali (‘a) said: "Surely, it is the common people of the community who are the pillars of the religion, the power of the Muslims and the defence against the enemies. Your leaning should therefore be towards them and your inclination with them."
Nahjul Balagha, Letter 53
Imam as-Sadiq (‘a) said: "In no way is Allah worshipped better than by fulfilling the right of a believer."
Al-Kafi, Vol.2, p. 170
The Holy Prophet (S) said: "He who hurts a Muslim believer, surely he has hurt me."
Bihar-ul-Anwar, vol. 67, p. 72
The Holy Prophet (S) said: "He who unlawfully and usurpingly deprives a believer of wealth, Allah will continue to be displeased with him and does not accept his good actions that he fulfills; and none of them will be recorded among his good deeds until he repents and returns the wealth which he had taken to its owner."
Mustadrak-ul-Wasa'il, vol. 17, p. 89