Leviticus 18:24-28

24Defile not ye yourselves in any of these things: for in all these the nations are defiled which I cast out before you: 25And the land is defiled: therefore I do visit its iniquity upon it, and the land itself spueth out her inhabitants. 26Ye shall therefore keep my statutes and my judgments, and shall not commit any of these abominations; neither any of your own nation, nor any stranger that sojourneth among you: 27(For all these abominations have the men of the land done, who were before you, and the land is defiled;) 28That the land may not spue you out also, when ye defile it, as it spued out the nations that were before you.