Musnad Abu Ya'la al-Mawsili 79:1

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