These Religious people follow their own experiences (influenced by evil spirits), rather than the plain meaning of the Word of God. They believe "the dead" will convey the will of God to them:
13 The LORD of hosts, Him you shall hallow; Let Him be your fear, And let Him be your dread.
14 He will be as a sanctuary, But a stone of stumbling and a rock of offense To both the houses of Israel, As a trap and a snare to the inhabitants of Jerusalem.
15 And many among them shall stumble; They shall fall and be broken, Be snared and taken."
16 Bind up the testimony, Seal the law among my disciples.
17 And I will wait on the LORD, Who hides His face from the house of Jacob; And I will hope in Him.
18 Here am I and the children whom the LORD has given me! We are for signs and wonders in Israel From the LORD of hosts, Who dwells in Mount Zion.
19 And when they say to you, "Seek those who are mediums and wizards, who whisper and mutter," should not a people seek their God? Should they seek the dead on behalf of the living?
20 To the law and to the testimony! If they do not speak according to this word, it is because there is no light in them.
21 They will pass through it hard pressed and hungry; and it shall happen, when they are hungry, that they will be enraged and curse their king and their God, and look upward.
22 Then they will look to the earth, and see trouble and darkness, gloom of anguish; and they will be driven into darkness. (Isa. 8:13-9:1 NKJ)
These "believers" suppose God is leading them through dreams, visions and voices via "the dead". But evil spirits disguise themselves as "good spirits" and "human dead" and telepathically cause people to have dreams, visions and hear voices or "voice-thought-impressions.
In contrast, true disciples of Christ are bound to the Word of God. God's Word is sealed in their hearts.
So, the "spiritists" (they don't know they are such) believe God has sent them to a foreign land.
As they pass through it they become hard-pressed and hungry, run out of money and food. At first, they rage and curse their leader for their misfortune, and then God for sending them to that horrible place.
But God didn't send them, their dreams visions and voices were a strong deluding influence, the "working of Satan".
That is what sent them, and they took pleasure in that unrighteousness. Thinking they were special, better than everyone else. They received not the love of the Truth, the Bible...so God gave them over to falsehood.
As they curse the God of heaven they look up to see what He will do and God grants them their first real vision from the Holy Spirit.
Then they look down and see the horrible pit, the lowest sheol.
Nothing but trouble, darkness, thick gloom and anguish awaits their souls when Hell swallows them up.
Then God thrusts them down into it, for not obeying His Word as Christ's Disciples did, the law and the testimony, the plain meaning of God's Word, the Holy Scriptures.