Musannaf Ibn Abi Shayba 34:201

Yazid narrated to us, from al-Mas'udi, from 'Amr, from 'Ubayd ibn al-Khashkhash, from Abu Dharr, who said: I entered upon the Messenger of Allah, may Allah bless him and grant him peace, while he was in the mosque. I said, "Which of the prophets was the first?" He said, "Adam." I said, "And was he a prophet?" He said, "Yes, a prophet who was spoken to."