Musnad Ahmad 30:1664

Al-Khuza'i narrated to us, he said: Sulayman narrated to us, from al-'Ala' ibn 'Abd al-Rahman, from his father, from Abu Hurayrah, that the Prophet, peace and blessings of Allah be upon him, said: "Trim the mustaches, let the beards grow, and differ from the Magians."