Musnad Abu Ya'la al-Mawsili 3:265

Muhammad ibn Bakkar narrated to us, Hudayj ibn Mu'awiyah narrated to us, from Abu Ishaq, from Abu Hudhayfah, from Ali, from the Prophet, may Allah bless him and grant him peace, that he said: "I saw the moon on the Night of Decree as if it were a piece of a bowl."