(1) باب وَقْتِهَا
Jundab b. Sufyan reported:
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.
Reference: Sahih Muslim 1960 a
In-book reference: Book 35, Hadith 1
USC-MSA web (English) reference(deprecated numbering scheme): Book 22, Hadith 4818