Al-Aswad narrates that Sayyiduna Jundub (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) led the prayer and then said: "Whoever slaughtered his sacrifice before the prayer, let him slaughter another in its place; and whoever has not slaughtered, let him slaughter with the name of Allah."
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1705