I do not know if the OP is still around - but this question is the most profound of all in christian practice.
And most of you will NOT like the answer!
The OP hit the nail on the head. You can be certain that as you go to your "service" at your chosen church, that whatever your pastor preaches a specific biblical passage means, someone else in a congregation not far away - even in the same street - is preaching the passage means something else entirely. Often the result of these disagreements is a congregation will schism on the basis of differing opinions in which one group could not accept the conclusion of another. The problem is authority. Who decides disputes?
But there is only one truth. Only ONE way to be saved. So what went wrong?
"Sola scriptura" is what went wrong, empowering all to decide their own version of truth.
When they say "scripture disagrees" they mean THEIR OPINION of scripture disagrees.
But unless you have the right meaning for scripture, you do not have the word of God.
For instance - baptismal regeneration either is or is not true as the entry to the faith.. It cannot be optional or simultaneously true and untrue..
The eucharist either is or is not the real flesh of Jesus, and - if it is - it is necessary for eternal life. Jesus says so in John 6.
This matters to eternal life. Since it "is the flesh" of Jesus (quote justin), Paul tells us some have died profaning it! - regarding with other than total reverence is profaning it.
Some try to paper of the cracks by claiming that they all agree on "essentials" which is not true - the differences between groups are EVERY aspect of christian doctrine and profound in which groups believe complete opposites. Either once saved always saved is true or it is one of the worst corruptions of doctrine there ever was.
Alas the comment on "essentials" is further proof that sola scriptura fails. Because where in scripture does it tell you which parts are essential?
Where does scripture preach sola scriptura? It does not.
So how can we know what it true? Jesus says clearly that apostolic teaching is true.
He who hears them hears me.
That is the basis of our faith only those who are "SENT" have the true doctrine to hand down. (the actual meaning of tradition, greek word paradosis - to which Paul tells you to stay true) So the teachers are SENT.
And how can we know what the apostles taught? The meaning, not the words?
The answer is there is a massive amount of history to tell us.
The early church fathers taught by apostles tell us in copious writings what the early church was and what it believed.
Whilst it is true - the early fathers are not "inspired" , but when they all say EXACTLY the same you can be sure it is a true record of what the church was and what it believed.
So LONG BEFORE THERE WAS A NEW TESTAMENT, LONG BEFORE THE CREED, LONG BEFORE THE DOGMATIC STATEMENT OF THE TRINITY
The early church was a physical thing with a hierarchy.
We know from ignatius, iraneus and others that..
1/ There was a succession of bishops from the apostles that iraneus can identify to his time.
2/ Only that succession is the custodian of truth. Those who were "sent". Who handed down the faith "tradition" . the new testament came later.
3/ They all believed in baptismal regeneration. They practised infant baptism. The reformers do not have the power to change that.
4/ Those John taught state the eucharist IS a eucharsit of the "real flesh" valid only if presided by a bishop in succession. And it is necessary for salvation.
5/ they believed in the primacy of the bishop of Rome.
6/ Their bible was the septuagint - that is INCLUDING macabees and prayers for the dead (not the Jewish masoretic text). Jesus himslef quoted from the septuagint! Luther had no power to overturn GODS opinion of what scripture was!
7/ We even know from justin writing to the roman emperor marcus aurelius a few decades after christ (not least to dispel myths about cannibalism!) that the church met on sunday as a big group, with a service that comprised first readings then those not baptised must leave before the eucharist
So someone coming from the first decades would recognise the Catholic mass and eucharist. They would not recognise Not rock bands, grape juice , altar calls and a focal point of a sermon.
8/ That councils met with the power to bind and loose to decide points of doctrine which is why you took disputes to " the pillar and foundation of truth" . The church is a physical thing. It decided on such as "arianism" which is the origin of the creed.
All this really matters. The early fathers condemn those as not even christian who "confess not the eucharist to be the body and blood of our Lord"
And it believed all this from the beginning.
In short the early church was Catholic in form and belief.
It did not centre on a "jesus prayer" as entry to the faith for example - which is a modern day invention. As are "altar calls". The early church certainly was not calvinist, and did not believe in "once saved always saved".
It believed in baptismal regeneration, and a eucharist as the source and summit of the faith.
If you doubt any of this ask yourself a question.
If sola scriptura was valid. Why did none of the reformers even agree with each other? Zwingli, calvin and luther were poles apart.
Modern day lutherans do not agree with luther. Modern day calvinists donot agree with calvin!
You would be amazed if you knew what luther believed about mary!
And Why did the reformers mess with scripture? Who gave them the right?
Doctrine is a three legged stool. Scritpure . Tradition (the faith handed down by the succession). Authority (by councils weilding the power to bind and loose) resolves disputes.
Lose any of the legs and the stool falls over.
In short if you want the truth study what the apostolic faith was. Read the early church fathers.
They give you a clear picture of what the early church belieevd. Some learned from the apostles themselves.
