Leviticus 18:3, 27-30

You shall not do as they do in the land of Egypt, where you lived, and you shall not do as they do in the land of Canaan, to which I am bringing you. You shall not walk in their statutes.

(for the people of the land, who were before you, did all of these abominations, so that the land became unclean), lest the land vomit you out when you make it unclean, as it vomited out the nation that was before you. For everyone who does any of these abominations, the persons who do them shall be cut off from among their people. So keep my charge never to practice any of these abominable customs that were practiced before you, and never to make yourselves unclean by them: I am the LORD your God.”