Musnad Ahmad 30:687

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him; and Muhammad ibn Ziyad, from Abu Hurayrah, that the Messenger of Allah, peace and blessings of Allah be upon him, said: "When the servant of one of you brings his food, having attended to its heat, its hardship, its smoke, and its preparation, let him make him sit with him. If he refuses, then let him hand him a morsel in his hand."