'ôb (אוֹב, Strong's #178), “spirit (of the dead); necromancer; pit.” This word has cognates in Sumerian, Akkadian, and Ugaritic, where the meanings “pit” and “spirit of one who has died” occur. In its earliest appearances (Sumerian), 'ôb refers to a pit out of which a departed spirit may be summoned. Later Assyrian texts use this word to denote simply a pit in the ground. Akkadian texts describe a deity that is the personification of the pit, to whom a particular exorcism ritual was addressed. Biblical Hebrew attests this word 16 times.
The word usually represents the troubled spirit (or spirits) of the dead. This meaning appears unquestionably in Isa. 29:4: “… Thy voice shall be, as of one that hath a familiar spirit, out of the ground, and thy speech shall whisper out of the dust.” Its second meaning, “necromancer,” refers to a professional who claims to summon forth such spirits when requested (or hired) to do so: “Regard not them that have familiar spirits, neither seek after wizards” (Lev. 19:31—first occurrence). These mediums summoned their “guides” from a hole in the ground. Saul asked the medium (witch) of Endor, “Divine for me from the hole ['ôb] (1 Sam. 28:8, author’s translation).
God forbade Israel to seek information by this means, which was so common among the pagans (Lev. 19:31; Deut. 18:11). Perhaps the pagan belief in manipulating one’s basic relationship to a god (or gods) explains the relative silence of the Old Testament regarding life after death. Yet God’s people believed in life after death, from early times (e.g., Gen. 37:35; Isa. 14:15ff.) Necromancy was so contrary to God’s commands that its practitioners were under the death penalty (Deut. 13). Necromancers’ unusual experiences do not prove that they truly had power to summon the dead. For example, the medium of Endor could not snatch Samuel out of God’s hands against His wishes. But in this particular incident, it seems that God rebuked Saul’s apostasy, either through a revived Samuel or through a vision of Samuel. Mediums do not have power to summon the spirits of the dead, since this is reprehensible to God and contrary to His will.