Sunan an-Nasa'i, Book 22, Hadith 338 (In-Book) ⓘ
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."
أَخْبَرَنَا أَحْمَدُ بْنُ عُثْمَانَ بْنِ حَكِيمٍ، عَنْ بَكْرٍ، عَنْ عِيسَى، عَنْ مُحَمَّدٍ، عَنِ الْحَكَمِ، عَنْ مُوسَى بْنِ طَلْحَةَ، عَنِ ابْنِ الْحَوْتَكِيَّةِ، قَالَ قَالَ أُبَىٌّ جَاءَ أَعْرَابِيٌّ إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم وَمَعَهُ أَرْنَبٌ قَدْ شَوَاهَا وَخُبْزٌ فَوَضَعَهَا بَيْنَ يَدَىِ النَّبِيِّ صلى الله عليه وسلم ثُمَّ قَالَ إِنِّي وَجَدْتُهَا تَدْمَى . فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لأَصْحَابِهِ " لاَ يَضُرُّ كُلُوا " . وَقَالَ لِلأَعْرَابِيِّ " كُلْ " . قَالَ إِنِّي صَائِمٌ . قَالَ " صَوْمُ مَاذَا " . قَالَ صَوْمُ ثَلاَثَةِ أَيَّامٍ مِنَ الشَّهْرِ . قَالَ " إِنْ كُنْتَ صَائِمًا فَعَلَيْكَ بِالْغُرِّ الْبِيضِ ثَلاَثَ عَشْرَةَ وَأَرْبَعَ عَشْرَةَ وَخَمْسَ عَشْرَةَ " . قَالَ أَبُو عَبْدِ الرَّحْمَنِ الصَّوَابُ عَنْ أَبِي ذَرٍّ وَيُشْبِهُ أَنْ يَكُونَ وَقَعَ مِنَ الْكُتَّابِ ذَرٌّ فَقِيلَ أُبَىٌّ .
also referenced under: Hadith 2427 (Reference) & Volume 3, Book 22, Hadith 2429 (DarusSalam)