Sahih Muslim 827b
Qaza'a related from Abu Sa'id. He said: I heard from him (Abu Sa'id) a hadith which impressed me, and I said to him: Did you hear it from the Messenger of Allah ﷺ? Thereupon he said: (Is it possible) that (I should) say about the Messenger of Allah ﷺ that which I have not heard? I heard him saying: It is not proper to fast on two days, Adha and Fitr (at the end) of Ramadan.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا جَرِيرٌ، عَنْ عَبْدِ الْمَلِكِ، - وَهُوَ ابْنُ عُمَيْرٍ - عَنْ قَزَعَةَ، عَنْ أَبِي سَعِيدٍ، - رضى الله عنه - قَالَ سَمِعْتُ مِنْهُ، حَدِيثًا فَأَعْجَبَنِي فَقُلْتُ لَهُ آنْتَ سَمِعْتَ هَذَا، مِنْ رَسُولِ اللَّهِ ﷺ قَالَ فَأَقُولُ عَلَى رَسُولِ اللَّهِ ﷺ مَا لَمْ أَسْمَعْ قَالَ سَمِعْتُهُ يَقُولُ " لاَ يَصْلُحُ الصِّيَامُ فِي يَوْمَيْنِ يَوْمِ الأَضْحَى وَيَوْمِ الْفِطْرِ مِنْ رَمَضَانَ " .