Musnad Abu Ya'la al-Mawsili 107:15

Kamil ibn Talhah narrated to us, Ibn Lahi'ah narrated to us, Yazid ibn Abi Habib narrated to us, from Abu al-Khayr, from Uqbah: That the Messenger of Allah (peace and blessings of Allah be upon him) prayed over the martyrs of Uhud after eight years, like one bidding farewell to the living and the dead. He said: "Indeed, before you are precursors, and I am a witness over you. Your appointed meeting place is the Basin (al-Hawd), and I am looking at it from this place of mine. Its width is as that which is between Ayla and al-Juhfah. I have been given the keys to the treasures of the earth while I am in this station of mine. I do not fear for you that you will commit shirk (polytheism) after me, but I fear for you the world, that you might compete for it." Uqbah said: "That was the last look I had of the Messenger of Allah (peace and blessings of Allah be upon him)."