Sayyiduna Jarir (may Allah be pleased with him) said: "I pledged allegiance to the Messenger of Allah (peace and blessings be upon him) on Islam, and he (peace and blessings be upon him) held back his hand in order to stipulate for me sincere goodwill towards every Muslim."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 2495