1 Corinthians 8:4

Concerning eating things offered to idols, we know that an idol is nothing in the world, and that there is no other God but one.

1 Corinthians 10:19-20

What then do I say? that an idol sacrifice is any thing, or that an idol is any thing?

1 Timothy 4:1

But the Spirit says expressly, that in the last times some shall apostatize from the faith, attending to lying spirits and doctrines of demons,

Revelation 9:20

And the rest of men, who were not killed with these plagues, did not change their minds [to turn] from the works of their hands, not to worship demons and idols of gold and silver and brass and stone and wood, which cannot 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
But what the gentiles sacrifice, they sacrifice to demons, and not to God; and I do not wish you to be partakers with demons.
1 Timothy 4:1
But the Spirit says expressly, that in the last times some shall apostatize from the faith, attending to lying spirits and doctrines of demons,
Revelation 9:20
And the rest of men, who were not killed with these plagues, did not change their minds [to turn] from the works of their hands, not to worship demons and idols of gold and silver and brass and stone and wood, which cannot see nor hear nor walk,

Not to god

1 Corinthians 8:4
Concerning eating things offered to idols, we know that an idol is nothing in the world, and that there is no other God but one.
1 Corinthians 10:19
What then do I say? that an idol sacrifice is any thing, or that an idol is any thing?