Leviticus 20:6-7, 27

‘As for the person who turns to mediums [who consult the dead] or to spiritists, to play the prostitute after them, I shall set My face against that person and will cut him off from his people [excluding him from the atonement made for them]. [Is 54:5] You shall consecrate yourselves therefore, and be holy; for I am the LORD your God.

‘A man or woman who is a medium [who pretends to consult the dead] or who is a spiritist shall most certainly be put to death, and be stoned with stones; their blood is on them.’ ”