Familiar spirit
Sorcerers or necormancers, who professed to call up the dead to
answer questions, were said to have a “familiar spirit” (Deut. 18:11; 2 Kings 21:6; 2 Chr. 33:6; Lev. 19:31; 20:6; Isa. 8:19;
29:4). Such a person was called by the Hebrews an ’ob, which
properly means a leathern bottle; for sorcerers were regarded as
vessels containing the inspiring demon. This Hebrew word was
equivalent to the pytho of the Greeks, and was used to denote
both the person and the spirit which possessed him (Lev. 20:27;
1 Sam. 28:8; comp. Acts 16:16). The word “familiar” is from the
Latin familiaris, meaning a “household servant,” and was
intended to express the idea that sorcerers had spirits as their
servants ready to obey their commands.