Now regarding your question about food that has been offered to idols. Yes, we know that "we all have knowledge" about this issue. But while knowledge makes us feel important, it is love that strengthens the church.
But we know that there is only one God, the Father, who created everything, and we live for him. And there is only one Lord, Jesus Christ, through whom God made everything and through whom we have been given life.
However, not all believers know this. Some are accustomed to thinking of idols as being real, so when they eat food that has been offered to idols, they think of it as the worship of real gods, and their weak consciences are violated.
For if others see you-- with your "superior knowledge"-- eating in the temple of an idol, won't they be encouraged to violate their conscience by eating food that has been offered to an idol?
So if what I eat causes another believer to sin, I will never eat meat again as long as I live-- for I don't want to cause another believer to stumble.