Musnad Ahmad 1313:1

Sufyan ibn 'Uyaynah narrated to us, from 'Abd al-Karim, from 'Abdullah ibn al-Harith, who said: My father married me off during the caliphate of 'Uthman, and he invited a group of the companions of the Messenger of Allah, peace and blessings of Allah be upon him. Safwan ibn Umayyah came, and he was a very old man, and he said: "The Messenger of Allah, peace and blessings of Allah be upon him, said: 'Gnaw the meat with your teeth, for it is more wholesome and more digestible' — or: 'more appetizing and more digestible.'" Sufyan said: The doubt is from me or from him.