Musnad Ahmad 446:2

Abu al-Mughirah narrated to us, he said: al-Awza'i narrated to us, he said: Usayd ibn 'Abd al-Rahman narrated to me, he said: Salih ibn Jubayr narrated to me, he said: Abu Jum'ah narrated to me, he said: We ate lunch with the Messenger of Allah, may Allah bless him and grant him peace, and with us was Abu 'Ubaydah ibn al-Jarrah. He said: He said, "O Messenger of Allah, is there anyone better than us? We accepted Islam with you and performed Jihad with you." He said, "Yes, a people who will be after you; they will believe in me and they have not seen me."