Zevachim 4:5-6

Zevachim 4:5

Sacrifices of non-Jews do not render one liable for kareis because of piggul, nosar or ritual impurity, and one is not liable for slaughtering them outside; this is the opinion of Rabbi Meir but Rabbi Yosi says that one is liable for these things. Things that do not render one liable for piggul can still render one liable for nosar and for ritual impurity except for blood. Rabbi Shimon says that this applies to things that are normally eaten but things like wood, frankincense and incense do not render one liable to kareis for ritual impurity.

Zevachim 4:6

A person must have six things in mind when slaughtering a sacrifice: what type of sacrifice he is intending to offer, the person for whom it is being brought, that it is a sacrifice to God, that it is to be burned on the altar, for the sake of the aroma, in order to please God. When offering a sin offering or a guilt offering, one must also have in mind the sin for which it is meant to atone. Rabbi Yosi said that even if a person had none of these things in mind, the sacrifice is still valid because it is a condition of the court that intention is determined by the one offering the sacrifice (as opposed to the owner who brought it).