The Alaqi reported that he prayed alongside the Messenger of Allah ﷺ on the day of the sacrifice. When the Messenger of Allah ﷺ finished, he saw meat from sacrificed animals already prepared, and he realized that they had been slaughtered before he had performed the prayer. So the Messenger of Allah ﷺ said, "Whoever slaughtered before we prayed must slaughter another animal in its place, and whoever has not yet slaughtered until after we prayed should now slaughter in the name of Allah."
حدثنا عبيدة بن حميد حدثني الأسود بن قيس
ثم العلقي أنه صلى مع رسول الله ﷺ يوم أضحى فانصرف رسول الله ﷺ فإذا هو باللحم وذبائح الأضحى فعرف رسول الله ﷺ أنها ذبحت قبل أن يصلي فقال رسول الله ﷺ من كان ذبح قبل أن نصلي فليذبح مكانها أخرى ومن لم يكن ذبح حتى صلينا فليذبح باسم الله