Bara bin Azib reported,

The Prophet ﷺ went out on the day of Eid al-Adha to al-Baqi, where he prayed two rakahs. Then he turned his face toward us and said, "The first act of worship for us on this day of ours is to begin with the prayer, then return and offer the sacrifice. Whoever does this has followed our practice, and whoever slaughters before that has only offered something he hastened for his family, with nothing of the sacrifice about it."A man stood up and said, "Messenger of Allah, I have already slaughtered, but I have a young goat with me that is better than a mature one."He said, "Sacrifice it, but it will not suffice for anyone after you."

Bukhari 976

Sahih

حدثنا أبو نعيم قال حدثنا محمد بن طلحة عن زبيد عن الشعبي

عن البراء قال

خرج النبي ﷺ يوم أضحى إلى البقيع فصلى ركعتين ثم أقبل علينا بوجهه وقال إن أول نسكنا في يومنا هذا أن نبدأ بالصلاة ثم نرجع فننحر فمن فعل ذلك فقد وافق سنتنا ومن ذبح قبل ذلك فإنما هو شيء عجله لأهله ليس من النسك في شيء فقام رجل فقال يا رسول الله إني ذبحت وعندي جذعة خير من مسنة قال اذبحها ولا تفي عن أحد بعدك

البخاري 976صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Two Eids
Chapter
Imam facing the people during the Eid sermon
Numbering
Darussalam 976
Bukhari 976