I was with Allah’s Messenger (ﷺ) on the day of ‘Id al-Adha. While he had not returned after having offered (the Id prayer) and finished it, he saw the flesh of the sacrificial animals which had been slaughtered before he had completed the prayer. Thereupon he (the Holy Prophet) said: One who slaughtered his sacrificial animal before his prayer or our prayer (‘Id), he should slaughter another one in its stead, and he who did not slaughter, he should slaughter by reciting the name of Allah.
I was with Allah’s Messenger (ﷺ) (on the occasion) of ‘Id al-Adha. After he had completed the prayer with people, he found that the goats had been slaughtered, whereupon he said: He who slaughtered sacrificial animal before the prayer should slaughter a goat (again) in its stead and he who has not slaughtered he should slaughter it by reciting the name of Allah.
I heard Allah’s Messenger (ﷺ) as saying: I shall be there at the Cistern before you.