Musnad Ahmad 20:9

Nasr ibn Bab narrated to us, from Hajjaj, from Qatadah, from Abdullah ibn Ja'far, that he said: The last thing I saw of the Messenger of Allah, may Allah bless him and grant him peace, was that in one of his hands were fresh dates, and in the other was a cucumber. He was eating from this and biting from that. And he said: "The best of the sheep is the meat of the back."