Isa 8:19
It is to this ecclesiola in ecclesia that the prophet’s admonition is addressed. “And when they shall say to you, Inquire of the necromancers, and of the soothsayers that chirp and whisper:-Should not a people inquire of its God? for the living to the dead?” The appeal is supposed to be made by Judaeans of the existing stamp; for we know from Isa 2:6; Isa 3:2-3, that all kinds of heathen superstitions had found their way into Jerusalem, and were practised there as a trade. The persons into whose mouths the answer is put by the prophet (we may supply before Isa 8:19, “Thus shall ye say to them;” cf., Jer 10:11), are his own children and disciples. The circumstances of the times were very critical; and the people were applying to wizards to throw light upon the dark future. 'Ob signified primarily the spirit of witchcraft, then the possessor of such a spirit (equivalent to Baal ob), more especially the necromancer. Yidd‛oni, on the other hand, signified primarily the possessor of a prophesying or soothsaying spirit (πύθων or πνεῦμα τοῦ πύθωνος), Syr. yodūa‛ (after the intensive from pâ‛ul with immutable vowels), and then the soothsaying spirit itself (Lev 20:27), which was properly called yiddâ'ōn (the much knowing), like δαίμων, which, according to Plato, is equivalent to δαήμων. These people, who are designated by the lxx, both here and elsewhere, as ἐγγαστρόμυθοι, i.e., ventriloquists, imitated the chirping of bats, which was supposed to proceed from the shadows of Hades, and uttered their magical formulas in a whispering tone.
What an unnatural thing, for the people of Jehovah to go and inquire, not of their won God, but of such heathenish and demoniacal deceivers and victims as these (dârash 'el, to go and inquire of a person, Isa 11:10, synonymous with shâ'ar b', 1Sa 28:6)! What blindness, to consult the dead in the interests of the living! By “the dead” (hammēthim) we are not to understand “the idols” in this passage, as in Psa 106:28, but the departed, as Deu 18:11 (cf., 1 Sam 28) clearly proves; and בּעד is not to be taken, either here or elsewhere, as equivalent to tachath (“instead of”), as Knobel supposes, but, as in Jer 21:2 and other passages, as signifying “for the benefit of.” Necromancy, which makes the dead the instructors of the living, is a most gloomy deception.