Sayyiduna Ka'b bin Malik (may Allah be pleased with him) said: In the last sermon that we heard from the Messenger of Allah (peace and blessings be upon him), he (peace and blessings be upon him) said: "O company of the Muhajirun! You are increasing in number, while the Ansar have reached their limit. They are my confidants with whom I took refuge, so honour those of them who do good and overlook those of them who do wrong."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16208