And the 89th prohibition is that we are forbidden from offering any sacrifice outside, i.e., outside the courtyard of the Temple. This prohibited action is called, ma'aleh bachutz.

The source of this commandment is G‑d's statement1 (exalted be He), "Be careful not to offer your burnt-offerings in just any place that you may see fit."

In the words of the Sifri,2 "This verse only speaks of burnt-offerings. What is the source to apply this law to all sacrifices? It is the verse,3 'Only there shall you prepare all [the offerings] I have commanded you.' But one could still think that for a burnt-offering there is both a positive commandment and a prohibition, whereas for other sacrifices only a positive commandment! The Torah therefore says,4 'Only there shall you sacrifice burnt-offerings.' Burnt-offerings were already included; why, then, were they singled out? This was done to make a hekesh:5 just as burnt-offerings are specifically mentioned as coming under both the positive commandment and the prohibition, so too all sacrifices which come under the positive commandment come under the prohibition."

Although the explanation of this verse is simple, I will explain it to you in order to clarify the subject:

The burnt-offering has a verse which prohibits its being sacrificed outside, i.e., G‑d's statement,6 "[Be careful] not to offer your burnt-offerings [in just any place that you may see fit]." Another verse commands that the burnt-offering must be sacrificed inside, i.e. His statement,7 "Only there shall you sacrifice burnt-offerings," which is a positive commandment to sacrifice the burnt-offering "in the place G‑d shall choose"8 [i.e., the Temple].

Other sacrifices, however, are only mentioned as having the positive commandment to be sacrificed inside, from His state­ment,9 "Only there shall you sacrifice all [the offerings] I have commanded you." The statement, "only there shall you sacrifice," does imply a prohibition against sacrificing outside; but we have a principle that a prohibition which is derived from a positive com­mandment is itself considered a positive commandment. This is the meaning of their statement [in Sifri], "But one could still think that ... for other sacrifices there is only a positive commandment!," i.e., that one who offers another kind of sacrifice outside would trans­gress only a prohibition which is derived from a positive commandment [rather than a regular prohibition].

The verse,10 "'Only there shall you sacrifice burnt-offerings" [which seems extra, since the other half of the verse includes all sacrifices, including the burnt-offering], is therefore written to create a means of comparing all offerings to the burnt-offering: just as one who offers a burnt-offering outside transgresses a prohibition, so too there is a prohibition for all offerings.

One who transgresses this prohibition intentionally is punished by kares, and if unintentionally, must bring a sin-offering. The verse which mentions kares for one who is ma'aleh bachutz is in the portion of Acharei Mos,11 "[One] who offers a burnt-offering or other sacrifice and does not bring it to the Communion Tent to present it to G‑d, that person shall be cut off [spiritually] from his people."

The Sifra12 says, "The verse, 'that person shall be cut off [spiritually] from his people,' states the punishment. From which verse do we derive the prohibition? From the verse,13 "Be careful not to offer your burnt-offerings...." In the words of the Talmud in tractate Zevachim:14 "For sacrificing [outside] there is written both the punishment and the prohibition. The punishment is from the verse, "and does not bring it to the Communion Tent ... that person shall be cut off." The prohibition is from the verse, "Be careful not to offer your burnt-offerings...."

The details of this mitzvah have been explained in the 13th chapter of tractate Zevachim.