It is narrated from Hazrat Uwaymir bin Ashqar (may Allah be pleased with him) that he once slaughtered the sacrificial animal before the Prophet Muhammad (peace and blessings be upon him). When the Prophet Muhammad (peace and blessings be upon him) finished the Eid prayer, he mentioned this to the Prophet (peace and blessings be upon him), and the Prophet (peace and blessings be upon him) ordered him to offer the sacrifice again.