Musnad Ahmad 31:332

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from 'Ubayd Allah ibn 'Abd Allah, or 'Ata' ibn Yazid—Ma'mar was uncertain—from Abu Sa'id al-Khudri, who said: A man said: "O Messenger of Allah, which of the people is best?" He said: "A believer who strives with his self and his wealth in the way of Allah." He said: "Then who?" He said: "Then a man who is secluded in a mountain pass, worshipping his Lord, the Mighty and Majestic, and leaving the people alone from his evil."