Musnad Ahmad 937:11

Ya'qub narrated to us, my father narrated to us, from Ibn Ishaq, Sulayman al-A'mash narrated to me, from Mujahid ibn Jabr Abu al-Hajjaj, from 'Ubayd ibn 'Umayr al-Laythi, from Abu Dharr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I have been given five things that no prophet before me was given: I have been aided by fear, so the enemy is struck with fear of me from a distance of a month's journey; the earth has been made a place of prostration and a means of purification for me; the spoils of war have been made lawful for me, and they were not made lawful for anyone before me; I have been sent to the red and the black; and it was said to me: 'Ask, and you shall be given.' So I reserved it as an intercession for my nation, and it shall be attained, if Allah wills, by whoever meets Allah not associating anything with Him." Al-A'mash said: Mujahid used to hold the view that "the red" refers to mankind, and "the black" refers to the jinn.