Sunan an-Nasa'i 2427

It was narrated that Ibn Al-Hawtakiyyah said:"Ubayy said: 'A Bedouin came to the Messenger of Allah, and he had a rabbit that he had grilled and some bread. He placed it before the Prophet then he said: "I found it bleeding." The Messenger of Allah said to his Companions: "It doesn't matter; eat." And he said to the Bedouin: "Eat," He said: "I am fasting." He said: "If you want to fast then you should fast the shining days of Al-Bid: The thirteenth, fourteenth and fifteenth