حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، سَمِعَ أَبَا عُبَيْدٍ
قَالَ شَهِدْتُ الْعِيدَ مَعَ عُمَرَ فَبَدَأَ بِالصَّلَاةِ قَبْلَ الْخُطْبَةِ وَقَالَ: إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَهَى عَنْ صِيَامِ هَذَيْنِ الْيَوْمَيْنِ أَمَّا يَوْمُ الْفِطْرِ فَفِطْرُكُمْ مِنْ صَوْمِكُمْ وَأَمَّا يَوْمُ الْأَضْحَى فَكُلُوا مِنْ لَحْمِ نُسُكِكُمْ
I was present at Eid with Umar, and he started with the prayer before the khutbah. He said: The Messenger of Allah (sallallahu alayhi wa sallam) forbade fasting on these two days. The day of al-Fitr is the day when you break your fast, and on the day of al-Adha, eat the meat of your sacrifices.
Musnad Ahmad 157, Book 2, Musnad `Umar b. al-Khattab (ra), Hadith 80. 1 min read