~ C.S. Lewis, Mere Christianity
In two sentences we have the matter boiled down to its essence. A lot of the strife we see is due to asking the wrong question.
No, I disagree with Lewis here. So does Paul, who insists that works have NOTHING to do with salvation: "And if by grace, it is not now by works: otherwise grace is no more grace" (Romans 11:5).
The seeming contradictions, e.g. Paul vs James, must be resolved in the clear light of Scripture which INSISTS that no flesh can be justified before God by works of the Law. One cannot be just a little bit justified. You either are or you are not! Scripture makes it clear that GOD is the One who justifies, and he does so based on BELIEVING, which is credited as righteousness.
It helps if you listen to Gods appointed apostles instead of the confused, layered cant of false teachers.