The Prophet (ﷺ) said (on the day of Idal-Adha), "The first thing we will do on this day of ours, is to offer the (`Id) prayer and then return to slaughter the sacrifice. Whoever does so, he acted according to our Sunna (tradition), and whoever slaughtered (the sacrifice) before the prayer, what he offered was just meat he presented to his family, and that will not be considered as Nusak (sacrifice)." (On hearing that) Abu Burda bin Niyar got up, for he had slaughtered the sacrifice before the prayer, and said, "I have got a six month old ram." The Prophet (ﷺ) said, 'Slaughter it (as a sacrifice) but it will not be sufficient for any-one else (as a sacrifice after you). Al-Bara' added: The Prophet (ﷺ) said, "Whoever slaughtered (the sacrifice) after the prayer, he slaughtered it at the right time and followed the tradition of the Muslims."
Sahih al-Bukhari Book 73, Hadith 1
← Previous Hadith While we were with the Prophet. on a journey, one of the camels ran away. A man shot it with an arrow and stopped it. The Prophet (ﷺ) said, "Of these camels some are as wild as wild beasts, so if one of them runs away and you cannot catch it, then do like this (shoot it with an arrow)." I said, "O Allah's Apostle! Sometimes when we are in battles or on a journey we want to slaughter (animals) but we have no knives." He said, "Listen! If you slaughter the animal with anything that causes its blood to flow out, and if Allah's Name is mentioned on slaughtering it, eat of it, provided that the slaughtering instrument is not a tooth or a nail, as the tooth is a bone and the nail is the knife of Ethiopians."

Sahih al-Bukhari Book 72, Hadith 69 Next Hadith → The Prophet (ﷺ) said, "Whoever slaughtered the sacrifice before the prayer, he just slaughtered it for himself, and whoever slaughtered it after the prayer, he slaughtered it at the right time and followed the tradition of the Muslims."

Sahih al-Bukhari Book 73, Hadith 2