1 Corinthians 8:4

Now as to eating food that has been offered to idols, we know well that an idol has no real existence in the universe, and that there is no God but One.

1 Corinthians 10:19-20

What then shall we say? that an offering to an idol is anything? or that an idol is really anything?

1 Timothy 4:1

Now the Spirit distinctly declares that in latter days there will be some who will fall away from the faith, by listening to spirits of error, and to teachings of demons

Revelation 9:20

And the rest of mankind who were not killed with these plagues, did not repent of the works of their hands. They would not give up the worship of demons and of idols made of gold and silver, and brass, and stone, and wood, which can neither see, nor hear, nor walk.

Treasury of Scripture Knowledge

Summary

They sacrificed unto devils, not to God; to gods whom they knew not, to new gods that came newly up, whom your fathers feared not.

Bible References

Sacrificed

1 Corinthians 10:20
On the contrary, what the heathen sacrifice they sacrifice to demons and not to God, and I do not want you to have communion with demons.
1 Timothy 4:1
Now the Spirit distinctly declares that in latter days there will be some who will fall away from the faith, by listening to spirits of error, and to teachings of demons
Revelation 9:20
And the rest of mankind who were not killed with these plagues, did not repent of the works of their hands. They would not give up the worship of demons and of idols made of gold and silver, and brass, and stone, and wood, which can neither see, nor hear, nor walk.

Not to god

1 Corinthians 8:4
Now as to eating food that has been offered to idols, we know well that an idol has no real existence in the universe, and that there is no God but One.
1 Corinthians 10:19
What then shall we say? that an offering to an idol is anything? or that an idol is really anything?