'Things Sacrificed to Idols' in the Bible

Then concerning the eating of the things sacrificed to idols, we know that an idol is nothing in the world, and that there is no other God except one.

For if anyone sees you who have knowledge sitting in an idol temple, will not the weak one's conscience be lifted up so as to eat things sacrificed to idols?

But I have a few things against you, because you have there those who hold the teachings of Balaam, who taught Balak to cast a stumbling-block before the sons of Israel, to eat things sacrificed to idols and to commit fornication.