First, let us be clear that divination, sorcery, necromancy, etc, were strictly forbidden in Israel:
Deut 18:9-12 - When you enter the land that the LORD your God is
giving you, do not imitate the detestable ways of the nations there.
Let no one be found among you who sacrifices his son or daughter in
the fire,a practices divination or conjury, interprets omens,
practices sorcery, casts spells, consults a medium or spiritist, or
inquires of the dead. For whoever does these things is detestable to
the LORD. And because of these detestable things, the LORD your God is
driving out the nations before you.
In fact, the northern kingdom of Israel was condemned for these practices and the prophets cited this as a significant contributor to their downfall and capture.
2 Kings 17:17 - They sacrificed their sons and daughters in the fire
and practiced divination and soothsaying. They devoted themselves to
doing evil in the sight of the LORD, provoking Him to anger.
Isaiah also preached a warning against divination and necromancy:
Isa 8:19, 20 - When men tell you to consult the spirits of the dead
and the spiritists who whisper and mutter, shouldn’t a people consult
their God instead? Why consult the dead on behalf of the living? To
the law and to the testimony! If they do not speak according to this
word, they have no light of dawn.
See Isa 44:25 for more of Isaiah's warnings against divination and necromancy.
Ezekiel issued a warning against false prophets who have practice divination and necromancy, see Eze 12:24, 13:6, 9, 23, 21:21, 29, 22:28. Jeremiah did the same thing, Jer 14:14, 27:9, 29:8; so did Zechariah, Zech 10:2; so did Micah in Mic 3:6
King Saul was condemned for consulting a necromancer in 1 Sam 28 & 31.
Therefore, the warning in Isa 19:3 is a warning to Egypt that such practices (consulting the dead) are no help and it will facilitate Egypt's downfall.
Actually, the Hebrew does not have the phrase "spirits of the dead"; the verse reads (my literal translation):
And will fail the spirit of Egypt in its midst; I will destroy their
counsel and they will consult unto idols, and unto charmers, and unto
mediums/necromancers and unto sorcerers.
Can the spirits of the dead be consulted? - definitely not! There are at least two reasons for this (apart from the fact this verse does not discuss that) -
- It is forbidden by the laws of the Bible and the prophets as documented above.
- The dead are dead and do not become ghosts as per:
- Man is unconscious in death. Eccl 9:5, 6, 10, Ps 6:5, Isa 38:18, Ps 88:10. Thus, the Bible very often calls death a “sleep”; Matt 9:24, Mark 5:39, Luke 8:52, John 11:11, 12, Acts 7:60, 13:36, 1 Cor 7:39, 11:30, 15:6, 18, 20, 51, 1 Thess 4:13-15, 5:10, 2 Peter 3:4, etc.
- The soul can be destroyed. Matt 10:28, Eze 18:4, 20, 24, Mal 4:1, 3.
- The soul cannot think after death. Ps 115:17, Job 14:2, 21, Ps 146:3, 4 “their thoughts perish, KJV).
- Man waits in the grave until the resurrection. Acts 2:29, 31, 32, John 11:11 – 14
Therefore, when mediums, spiritists and necromancers consult them, they are presumably communicating with demonic spirits (Rev 16:14, Matt 12:28, 1 Tim 4:1, etc.)