Pensée juive sur Isaïe 29:4

וְשָׁפַלְתְּ֙ מֵאֶ֣רֶץ תְּדַבֵּ֔רִי וּמֵֽעָפָ֖ר תִּשַּׁ֣ח אִמְרָתֵ֑ךְ וְֽ֠הָיָה כְּא֤וֹב מֵאֶ֙רֶץ֙ קוֹלֵ֔ךְ וּמֵעָפָ֖ר אִמְרָתֵ֥ךְ תְּצַפְצֵֽף׃

Tu descendras si bas que tu parleras comme de dessous terre et que tes paroles affaiblies sembleront sortir de la poussière; ta voix montera de terre, pareille à celle d’un spectre, et, comme un murmure, tes paroles s’élèveront du sol.

Akeidat Yitzchak

1) From what is known of the practice of an ov, it seems that the witch manipulates the bones of the dead, as a result of which a low voice communicates with the witch answering an enquiry directed at the dead. (Isaiah 29,4) Your voice will be as that of the ghost out of the ground, and your speech will chirp out of the dust." This sound then is considered as the dead having risen in response to the question. There is absolutely no basis for assuming that the questioner will see an image. There is certainly no question of spiritual beings responding by becoming visible as happened in the case of Saul at Endor. (Samuel I 28,12 )