Musnad Abu Ya'la al-Mawsili 148:96

Amr ibn al-Dahhak ibn Makhlad narrated to us, my father narrated to us, Shabib ibn Bishr narrated to us, from Anas ibn Malik, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Two eyes shall never be touched by the Fire: an eye that spent the night guarding the Muslims in the way of Allah, and an eye that wept out of fear of Allah."