Musnad Abu Ya'la al-Mawsili 159:39

Bishr ibn al-Walid narrated to us, Abd al-Rahman ibn Abi al-Zinad narrated to us, from his father, from Abd al-Rahman al-A'raj, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I have been aided by fear, and I have been given the concise speech. While I was sleeping, I was brought the keys to the treasures of the earth, and they were placed in my hand."