Sunan Abi Dawud, Hadith 2410 ⓘ
Narrated Abu 'Ubaid: I attended the 'Id (prayer) along with 'Umar. He offered prayer before the sermon. He then said: The Messenger of Allah prohibited fasting on these two days. As regards Id al-Adha, you eat the meat of your sacrificial animals. As for 'Id al-Fitr, you break (i.e. end) your fast.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَزُهَيْرُ بْنُ حَرْبٍ، - وَهَذَا حَدِيثُهُ - قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي عُبَيْدٍ، قَالَ شَهِدْتُ الْعِيدَ مَعَ عُمَرَ فَبَدَأَ بِالصَّلاَةِ قَبْلَ الْخُطْبَةِ ثُمَّ قَالَ إِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ صِيَامِ هَذَيْنِ الْيَوْمَيْنِ أَمَّا يَوْمُ الأَضْحَى فَتَأْكُلُونَ مِنْ لَحْمِ نُسُكِكُمْ وَأَمَّا يَوْمُ الْفِطْرِ فَفِطْرُكُمْ مِنْ صِيَامِكُمْ .
also referenced under: Hadith 2416 (DarusSalam)