Sunan an-Nasa'i 2217
Abu Hurairah said:
"The Messenger of Allah said: 'Allah, the Mighty and sublime, said: Every deed of the son of Adam is for him, except fasting; it is for me and I shall reward for it. Fasting is a shield. If any one of you is observing a fast, let him not utte obscene a fast, let him not utter obscene talk or raise his voice in anger, and if anyone insults him or wants to fight, let him say: I am a person who is fasting. By the One in Whose hand is the soul of Muhammad, the smell coming from the mouth of the fasting person is better before Allah than the fragrance of musk." ' (Sahih) 
This Hadith was narrated from Abu Hurairah by Saeed bin Al-Musayyab.
أَخْبَرَنَا مُحَمَّدُ بْنُ حَاتِمٍ، قَالَ أَنْبَأَنَا سُوَيْدٌ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، عَنِ ابْنِ جُرَيْجٍ، قِرَاءَةً عَلَيْهِ عَنْ عَطَاءِ بْنِ أَبِي رَبَاحٍ، قَالَ أَخْبَرَنِي عَطَاءٌ الزَّيَّاتُ، أَنَّهُ سَمِعَ أَبَا هُرَيْرَةَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ قَالَ اللَّهُ عَزَّ وَجَلَّ كُلُّ عَمَلِ ابْنِ آدَمَ لَهُ إِلاَّ الصِّيَامَ هُوَ لِي وَأَنَا أَجْزِي بِهِ الصِّيَامُ جُنَّةٌ فَإِذَا كَانَ يَوْمُ صَوْمِ أَحَدِكُمْ فَلاَ يَرْفُثْ وَلاَ يَصْخَبْ فَإِنْ شَاتَمَهُ أَحَدٌ أَوْ قَاتَلَهُ فَلْيَقُلْ إِنِّي امْرُؤٌ صَائِمٌ وَالَّذِي نَفْسُ مُحَمَّدٍ بِيَدِهِ لَخُلُوفُ فَمِ الصَّائِمِ أَطْيَبُ عِنْدَ اللَّهِ مِنْ رِيحِ الْمِسْكِ ‏"‏ ‏.‏ وَقَدْ رَوَى هَذَا الْحَدِيثَ عَنْ أَبِي هُرَيْرَةَ سَعِيدُ بْنُ الْمُسَيَّبِ ‏.‏