Levítico 19:31 Halacá: Mishneh Torah, Foreign Worship and Customs, Mishneh Torah, Negative Mitzvot & Sefer HaChinukh

How is spiritualism practiced? One puts a bone of a bird known to such practicioners in his mouth, burns incense and performs other manipulations until he falls into a fit resembling epilepsy, when he speaks out of his mouth happenings of the future. All such are forms of idolatry. Whencefrom is the warning against such practices derived? From what it is said: "Turn ye not unto the ghosts, nor unto familiar spirits" (Lev. 19.31)³Sifra, Lev. 19. C.

Not to consult ghosts, as it is said, “Turn ye not unto the ghosts” (Lev. 19:31).

Not to resort to familiar spirits as it is said, “…. nor to familiar spirits” (ibid.).