Musnad Ahmad

It is narrated from Hazrat Bara’ (may Allah be pleased with him) that once (on the day of Eid al-Adha) the Noble Prophet (peace and blessings be upon him) addressed us and said: Today, we will begin the day by offering the prayer, then return home and perform the sacrifice. Whoever does so has reached our way, and whoever performs the sacrifice before the Eid prayer, it is merely meat that he has given to his family beforehand; it has nothing to do with the sacrifice. My uncle, Hazrat Abu Burdah bin Niyar (may Allah be pleased with him), had already slaughtered his animal before the Eid prayer. He said, O Messenger of Allah (peace and blessings be upon him)! I have already slaughtered my animal, but now I have a six-month-old lamb which is better than a year-old animal. The Noble Prophet (peace and blessings be upon him) said, Sacrifice this in its place, but this will not suffice for anyone other than you.