Leviticus 20:6-8

And the soul that turneth unto them that have familiar spirits, and unto the wizards, to play the harlot after them, I will even set my face against that soul, and will cut him off from among his people. Sanctify yourselves therefore, and be ye holy; for I am Jehovah your God. And ye shall keep my statutes, and do them: I am Jehovah who sanctifieth you.