Musnad Ahmad 446:3

Abu al-Mughirah narrated to us, he said: al-Awza'i narrated to us, he said: Usayd ibn 'Abd al-Rahman narrated to me, from Khalid ibn Durayk, from Ibn Muhayriz, he said: I said to Abu Jum'ah—a man from the Companions—: "Narrate to us a hadith you heard from the Messenger of Allah, may Allah bless him and grant him peace." He said: "Yes, I will narrate to you a good hadith. We had 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: '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 you; they will believe in me, and they have not seen me."