Sunan Ibn Majah, Book 7, Hadith 1793 (In-Book) ⓘ

It was narrated that Abu ‘Ubaid said: “I was present for ‘Eid with ‘Umar bin Khattab. He started with the prayer before the sermon, and said: ‘The Messenger of Allah forbade fasting on these two days, the Day of Fitr and the Day of Adha. As for the Day of Fitr, it is the day when you break your fast, and on the Day of Adha you eat the meat of your sacrifices.’”

حَدَّثَنَا سَهْلُ بْنُ أَبِي سَهْلٍ، حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي عُبَيْدٍ، قَالَ شَهِدْتُ الْعِيدَ مَعَ عُمَرَ بْنِ الْخَطَّابِ فَبَدَأَ بِالصَّلاَةِ قَبْلَ الْخُطْبَةِ فَقَالَ إِنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ نَهَى عَنْ صِيَامِ هَذَيْنِ الْيَوْمَيْنِ يَوْمِ الْفِطْرِ وَيَوْمِ الأَضْحَى أَمَّا يَوْمُ الْفِطْرِ فَيَوْمُ فِطْرِكُمْ مِنْ صِيَامِكُمْ وَيَوْمُ الأَضْحَى تَأْكُلُونَ فِيهِ مِنْ لَحْمِ نُسُكِكُمْ ‏.‏