“Guard yourself lest you offer your burnt offerings in any place that you see” (Devarim 12,13)
It is a negative commandment not to slaughter sanctified animals outside the courtyard (of the temple) as it says, “Guard yourself lest you offer your burnt offerings in any place that you see”. The expression “offering up” which is mentioned here is the act of burning which is the way in which offerings are brought. This prohibition applies not only to burnt offerings (Korban Olah), which is understood in the verse, but applies also to all the rest of the types of sacrifice.
Amongst the roots of the commandment: since Hashem, may He be blessed, has established a place for the Jews to bring their offerings, and to prepare their hearts to serve Him there; through the establishment of the place, and the elevation of it and by the fear of it in the heart of a person, his soul is uplifted there for the good, his heart is softened and becomes submissive to accept completely the kingdom of heaven. Therefore, Hashem, may He be blessed, has prevented us from performing the act of offering in any other place so that the act of offering should be a complete atonement for us.
The prohibition against slaughtering outside the temple applies in every place, at all times. Even nowadays, one who slaughters an animal for the sake of an offering, deserves the penalty of kareis (being cut off from the Jewish people).