In the early church, the question of whether or not it was OK to eat meat that had been part of a sacrifice to pagan deities was a real issue, considering the amount of time Paul spent addressing it in his various letters. And before teaching how the Christians at Corinth were to handle it amongst themselves, Paul laid out the foundational truths involved.
In those days, as it still is today, there were many beings, in heaven and on earth, who were called gods and lords, and were worshipped by many. In fact, some people worshipped multiple gods. The emperor demanded worship as a god, the Greeks had their gods, the Romans had theirs. The Jews, in a strange departure from the nations around them, claimed one single God. And the new Christians were at odds with everybody, even the Jews, because they claimed that there was only one God, and that He has a Son Who is also God.
So in addressing how the Christians were to interact with other Christians of different backgrounds, and, indeed, how they were to interact with the world around them, Paul started with some definition. He re-iterated the basic fact of our faith, that there is only One God, and the idols which surround us are not really gods at all.
“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.” 1 Corinthians 8:6 NLT
The world, and everything in it, belongs to God Who made it. The man who believes in God and in Jesus Christ, who gives thanks to God for what He supplies, lives under the protection of God and can eat anything without fear. The pagan deities and idols have no power to contaminate what is cleansed by the word and power of God.
We live for the Only True God, Who tells us to call Him “Father.” The life that we live has been given to us by His Son, our Lord Jesus Christ. In Him, we have protection and cleansing, wisdom and love, sufficient for our needs as we live with others in a world full of idols.