It is narrated from Sayyiduna Mu'adh bin Anas al-Juhani (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The most excellent of virtues is that you maintain ties with the one who cuts you off, give to the one who deprives you, and pardon the one who reviles you."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17548