It is narrated from Sayyiduna Jariyah bin Qudamah (may Allah be pleased with him) that he said: O Messenger of Allah, tell me one thing about Islam that I can remember, and keep it brief. He (peace and blessings be upon him) said: "Do not become angry."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 2080