Musnad Ahmad 30:467

Abu Kamil narrated to us, Ibrahim narrated to us, Ibn Shihab narrated to us, from Sa'id ibn al-Musayyib, from Abu Hurairah, that the Prophet (peace and blessings of Allah be upon him) said: "I have been sent with the concise speech (jawami' al-kalim), and I have been aided by fear (al-ru'b). And while I was sleeping, I was brought the keys to the treasures of the earth, and they were placed in my hand."