Musannaf Ibn Abi Shayba 4:862

Hatim ibn Isma'il narrated to us, from 'Abd al-Rahman ibn Harmala, who said: I departed with Sa'id ibn al-Musayyib from the mosque, and we said, "This is the crescent moon, O Abu Muhammad." When he turned away, he said, "I believe in the One who created you, fashioned you, and balanced you." Then he turned to me and said, "When the Messenger of Allah, peace and blessings of Allah be upon him, saw the crescent moon, he would say like this."