Sahih Muslim Book - 13, Hadith - 2671

وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنِ ابْنِ شِهَابٍ عَنْ أَبِى عُبَيْدٍ مَوْلَى ابْنِ أَزْهَرَ أَنَّهُ قَالَ شَهِدْتُ الْعِيدَ مَعَ عُمَرَ بْنِ الْخَطَّابِ - رضى الله عنه - فَجَاءَ فَصَلَّى ثُمَّ انْصَرَفَ فَخَطَبَ النَّاسَ فَقَالَ إِنَّ هَذَيْنِ يَوْمَانِ نَهَى رَسُولُ اللَّهِ -صلى الله عليه وسلم- عَنْ صِيَامِهِمَا يَوْمُ فِطْرِكُمْ مِنْ صِيَامِكُمْ وَالآخَرُ يَوْمٌ تَأْكُلُونَ فِيهِ مِنْ نُسُكِكُمْ.

It was narrated that Abu Ubaid, the freed slave of Ibn Azhar, said: “I attended Id with Umar bin Al-Khattab [may Allah be please with them]. He came and prayed, then he stood and addressed the people saying: ‘These are two days when the Messenger of Allah forbade fasting, the day when you break your fast and the other day, when you eat from your sacrifices.”