The 85th prohibition is that we are forbidden from making incense according to the formula used in the ketores, i.e. composed of the same mixture of spices in the same measure, with the intention of using it for incense.
The source of this mitzvah is G‑d's statement1 (exalted be He), "[One who makes incense] shall not make it with this formula."
The Torah explains that one who intentionally transgresses this prohibition by making such a mixture with the intention of smelling its smoke receives kares, as it is written,2 "If a person makes it to enjoy its fragrance, he shall be cut off (nichras) from his people." If he did so unintentionally, he must bring a sin offering.
The details of this mitzvah are explained in the beginning of tractate Kerisus.3
