Isaiah 8:19

And when they(the infatuated, God-forsaken people) shall say unto you(believers in divine revelation).

them that have familiar spirits Hebr. simply hâ"ôbhôth. Strictly, the "ôbhis the "familiar spirit" itself (Leviticus 20:27, &c.), i.e. the disembodied spirit after death; the necromancer or "medium" through whom it holds communication with the living is ba-al "ôbhor ba-ǎlath "ôbh(1 Samuel 28:8) the possessor of an "ôbh.

wizards that peep, and that mutter "Wizards," lit. "knowing ones," practitioners of an occult science. Peep(i.e. chirp) and mutterrefer to the faint voice, like that of a little bird, which antiquity ascribed to the shades of the departed: "The sheeted dead did squeakand gibberin the streets of Rome." See ch. Isaiah 29:4, where the word "peep" is again used, and comp. Aen. 6:492 f.; Il. 23:101. The LXX. (τοὺς ἐνγαστριμύθους and οἳ ἐκ τῆς κοιλίας φωνοῦσιν) suggests that the voice of the ghost was imitated by ventriloquism, which is not unlikely.

should not a people … dead? This seems to be the answer which the prophet's disciples are to return to the people.

for the living to the dead? i.e. "should one enquire of the dead (ghost) on behalf of the living?"