Then what do you believe in, and why?
Well....I believe that scripture does interpret scripture, but only for the discerning. There are certain keys to scripture that some folks are just ignorant of and as such, some things are difficult to understand. Because of this some folks are easily led into error.
I'll give you a good example. [Colossians 2:14] and Ephesians 2:15] Both of these scripture deal with Paul speaking of "Ordinances" against us and the law of commandments contained in the "Ordinances". Now....most folks automatically read this thinking of the Ten Commandments when Paul is speaking of nothing of the sort. The reason for this is the inherent Anti Jewishness that has pervaded much of the mainstream church since Nicea.
The Greek word here translated Ordinances is "Dogma" and has nothing at all to do with Divine Law. This is the type of Law Our Savior speaks of in [Mark 7:7] Howbeit in vain do they worship me, teaching for doctrines the commandments of men. Paul is speaking of "Man Made" law....such as the Talmud.
Paul no where speaks of any of the Commandments of the Lord being abolished....and this would include the Sabbath command. But....yet we see the major Christian organizations disobeying this commandment every Sunday of the year. So, yes, we do need discernment when it comes to the scriptures. This would include relying on historical references, respected historians and even some of the statements of the Early Church Fathers themselves.....when it can be shown that they are in agreement with scripture.