Abu Dawud Book 16, Hadith Number 3326.
Narated By One of the Ansar : Asim ibn Kulayb quoted his father’s authority for the following statement by one of the Ansar: We went out with the Apostle of Allah (PBUH) to a funeral, and I saw the Apostle of Allah (PBUH) at the grave giving this instruction to the grave-digger:
Make it wide on the side of his feet, and make it wide on the side of his head. When he came back, he was received by a man who conveyed an invitation from a woman. So he came (to her), to it food was brought, and he put his hand (i.e. took a morsel in his hand); the people did the same and they ate. Our fathers noticed that the Apostle of Allah (PBUH) was moving a morsel around his mouth.
He then said: I find the flesh of a sheep which has been taken without its owner’s permission.
The woman sent a message to say: Apostle of Allah, I sent (someone) to an-Naqi’ to have a sheep bought for me, but there was none; so I sent (a message) to my neighbour who had bought a sheep, asking him to send it to me for the price (he had paid), but he could not be found. I, therefore, sent (a message) to his wife and she sent it to me.
The Apostle of Allah (PBUH) said: Give this food to the prisoners.