Sahih Muslim 1137
Abu Ubaid, the freed slave of Ibn Azhar, reported:
I observed Id along with Umar b. al-Khattab (Allah be pleased with him). He came (out in an open space) and prayed and (after) completing it addressed the people and said: The Messenger of Allah (ﷺ) has forbidden the observing of fast on these two days. One is the day of Fitr (at the end of your fasts), and the second one, the day when you eat (the meat) of your sacrifices.
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ ابْنِ شِهَابٍ عَنْ أَبِي عُبَيْدٍ مَوْلَى ابْنِ أَزْهَرَ أَنَّهُ قَالَ:
شَهِدْتُ الْعِيدَ مَعَ عُمَرَ بْنِ الْخَطَّابِ رَضِيَ اللَّهُ عَنْهُ فَجَاءَ فَصَلَّى ثُمَّ انْصَرَفَ فَخَطَبَ النَّاسَ فَقَالَ إِنَّ هَذَيْنِ يَوْمَانِ نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنْ صِيَامِهِمَا يَوْمُ فِطْرِكُمْ مِنْ صِيَامِكُمْ وَالْآخَرُ يَوْمٌ تَأْكُلُونَ فِيهِ مِنْ نُسُكِكُمْ