I attended the Eid with Umar, and he began with the prayer before the sermon. He said, "The Messenger of Allah ﷺ forbade fasting on these two days. As for the day of Fitr, it is your breaking of your fast. As for the day of Adha, eat from the meat of your sacrifices."
حدثنا سفيان عن الزهري سمع
شهدت العيد مع عمر فبدأ بالصلاة قبل الخطبة وقال إن رسول الله ﷺ نهى عن صيام هذين اليومين أما يوم الفطر ففطركم من صومكم وأما يوم الأضحى فكلوا من لحم نسككم
Its isnad is sahih. Abu Ubayd is Saad bin Ubayd, the freed slave of Ibn Azhar, also said to be the freed slave of Abdul-Rahman bin Awf. The hadith will come again at 224, 275, 282, and see also 427.