Why does 1 Corinthians 8 say an idol is nothing and there is no other God but one, even though there are many called gods and lords?
An idol is nothing because it possesses no real divinity; the many so-called gods and lords are only called gods. For believers, there is one God, the Father, of whom all things exist, and one Lord, Jesus Christ, by whom all things exist. Some Corinthians lacked this knowledge.
Les explains that the context is the eating of things offered in sacrifice to idols. The believer's knowledge is that an idol is nothing in the world, and there is no other God but one. Although there are many called gods and lords, whether in heaven or earth, to believers there is only one God, the Father, of whom are all things, and one Lord, Jesus Christ, by whom all things are, because He is Creator. Yet not every man has that knowledge. The Corinthian believers were still babes in Christ and did not have full comprehension of who and what God really is. Many believers today are saved but remain babes and lack that comprehension, and even long-time Christians find it beyond them.
As concerning therefore the eating of those things that are offered in sacrifice unto idols, we know that an idol is nothing in the world, and that there is none other God but one.
For though there be that are called gods, whether in heaven or in earth, (as there be gods many, and lords many,)
But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him.