The Book of Prayers (Kitab Al-Salat)
Muslim :: Book 4 : Hadith 1063
Abu Huraira reported: The Messenger of Allah (may peace be upon him) said: I have been commissioned with words which are concise but comprehensive in meaning; I have been helped by terror (in the hearts of enemies): and while I was asleep I was brought the keys of the treasures of the earth which were placed in my hand. And Abfi Huraira added: The Messenger of Allah (may peace be upon him) has left (for his heavenly home) and you are now busy in getting them.