Now about food sacrificed to idols: we know that, as you say, "We all have knowledge." Yes, that is so, but "knowledge" puffs a person up with pride; whereas love builds up.
The person who thinks he "knows" something doesn't yet know in the way he ought to know.
However, if someone loves God, God knows him.
So, as for eating food sacrificed to idols, we "know" that, as you say, "An idol has no real existence in the world, and there is only one God."
For even if there are so-called "gods," either in heaven or on earth - as in fact there are "gods" and "lords" galore -
yet for us there is one God, the Father, from whom all things come and for whom we exist; and one Lord, Yeshua the Messiah, through whom were created all things and through whom we have our being.
But not everyone has this knowledge. Moreover, some people are still so accustomed to idols that when they eat food which has been sacrificed to them, they think of it as really affected by the idol; and their consciences, being weak, are thus defiled.
Now food will not improve our relationship with God - we will be neither poorer if we abstain nor richer if we eat.
However watch out that your mastery of the situation does not become a stumbling block to the weak.
You have this "knowledge"; but suppose someone with a weak conscience sees you sitting, eating a meal in the temple of an idol. Won't he be built up wrongly to eat this food which has been sacrificed to idols?
Thus by your "knowledge" this weak person is destroyed, this brother for whom the Messiah died;
and so, when you sin against the brothers by wounding their conscience when it is weak, you are sinning against the Messiah!
To sum up, if food will be a snare for my brother, I will never eat meat again, lest I cause my brother to sin.