Have you ever heard the saying "Scripture interprets scripture"? It is a principle of hermeneuticswhich means that the passage you are looking at is evaluated
- In the sentence it appears in
- In the paragraph it appears in
- In the section it appears in
- In the book it appears in
- In other books by the same author
- In other books from that time period
- In the other books of that testament
- In the other books in the Bible
When you look at any scripture using that method there will ALWAYS be clarity of who is right and who has it wrong. You are correct I am not a catholic.
The authority of scripture rests on the scripture itself. It proves itself out. False, heretical teachings can not stand when you use that hermeneutical principle.
That's how we know that when someone says "God told me to kill..." they weren't from the God of scriptures. Because scripture time and time again forbids murder. It doesn't forbid war or capital punishment, but it forbids murder. As an example.
To cut the answer down to size if we were both reading the Bible and had a disagreement on certain things within we would search the scriptures until we had the right answer. It would be clear to both of us which position, if either, the Bible supports.