Sayyiduna Ubayy bin Ka'b (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said: "Whoever would be pleased to have his building raised high and his ranks elevated, let him pardon the one who wronged him, give to the one who deprived him, and keep ties with the one who cut him off."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 531