1 Corinthians 10:20-21

[Certainly not!] But I am saying that the Gentile sacrifices are [really] offered to evil spirits and not to God. And I do not want you to have fellowship with evil spirits.

1 Timothy 4:1

Now the Holy Spirit specifically says that in later times [Note: "Later times" in the New Testament usually refers to the period following the first coming of Christ and the establishment of the church], some people will fall away from the faith [i.e., the true teaching of Christianity]. They will pay attention to deceitful spirits [i.e., lying people] and the teaching of evil spirits.

Revelation 16:14

For they are spirits of demons, which perform [supernatural] signs. These spirits go out to the kings of the whole world to assemble them for battle on the great day of Almighty God.

Treasury of Scripture Knowledge

Summary

And he ordained him priests for the high places, and for the devils, and for the calves which he had made.

Bible References

For the devils

1 Corinthians 10:20
[Certainly not!] But I am saying that the Gentile sacrifices are [really] offered to evil spirits and not to God. And I do not want you to have fellowship with evil spirits.
1 Timothy 4:1
Now the Holy Spirit specifically says that in later times [Note: "Later times" in the New Testament usually refers to the period following the first coming of Christ and the establishment of the church], some people will fall away from the faith [i.e., the true teaching of Christianity]. They will pay attention to deceitful spirits [i.e., lying people] and the teaching of evil spirits.
Revelation 16:14
For they are spirits of demons, which perform [supernatural] signs. These spirits go out to the kings of the whole world to assemble them for battle on the great day of Almighty God.