It was narrated from Aswad bin Qais that he heard Jundub Al-Bajali say:“I was present on Adha day with the Messenger of Allah (ﷺ), and some people slaughtered before the prayer. The Prophet (ﷺ) said: ‘Whoever among you has slaughtered before the prayer, let him repeat his sacrifice, and whoever has not, let him offer his sacrifice in the Name of Allah.’”

English translation · Sunan Ibn Majah