Sayyiduna Jariyah bin Qudamah (may Allah be pleased with him) said: I said to the Messenger of Allah (peace and blessings be upon him): Tell me one thing about Islam, and keep it brief so that I can understand it and remember it. Then he related a similar hadith (that is, he (peace and blessings be upon him) said: "Do not become angry.").
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 2093