Isaiah 8:19 When men tell you to consult mediums and spiritists, who whisper and mutter, should not a people inquire of their God? Why consult the dead on behalf of the living?
1 Timothy 4:1 The Spirit clearly says that in later times some will abandon the faith and follow deceiving spirits and things taught by demons.
2 Corinthians 11:14-15 But I am not surprised! Even Satan can disguise himself as an angel of light. So it is no wonder his servants can also do it by pretending to be godly ministers. In the end they will get every bit of punishment their wicked deeds deserve.
2 Thessalonians 2:9-10 The coming of the lawless one will be in accordance with the work of Satan displayed in all kinds of counterfeit miracles, signs and wonders, and in every sort of evil that deceives those who are perishing. They perish because they refused to love the truth and so be saved.
They’re not dead.
This is an admonition against the evils of Calvinism.