We can go on forever about the interpretation of Christ’s death. It sure opened the door to salvation to all of us but that doesn’t mean we get a free pass. This brings us back to the initial proposition, namely the authentic teachings of Christ as reflected not only in scripture, but in all what was handed down to the Apostles and their successors including those acts that were recorded and those that were not, what Christ said that was written and what was not written. Scripture alone won’t cut it. This is why in establishing His Church on earth He entrusted to Peter the keys to the Kingdom of Heaven. “Whatsoever thou shall bind on earth will be bound in heaven and whatsoever thou shall loosen on earth, shall be loosened in Heaven.”
And again we revert to the threshold question. Whose interpretation of Scripture, revelation, and tradition do we accept? You have on one hand the Catholic Church and on the other hand some 35, 000 other Christian denominations including the likes of Joel Osteen; “Bishop” TD Jake; Rev. Sharpton; Rev. Wright; David Koresh; Rev. Jim Jones; or gay and lesbian ordinations of Christian bishops like Lutherans, Episcopalians, and Anglicans or simply trust you own interpretation and judgment like what the Gnostics tried to do? To ask this question is to answer it.
Please don't revert to this straw man argument! First of all, there are NOT 35,000 other Christian denominations. That bogus number has been disputed so many times here it is crazy to have to do so yet again. Secondly, it is pretending to think that the Catholic Church is unified on all questions of doctrine and dogma. It is a sham and there are numerous polls that prove beyond doubt that such unity is a pipe dream. Though "officially" there are stated beliefs and doctrines, only a small minority, if that, holds dogmatically to each and every one. I doubt you could get all those cardinals gathering in Rome to universally agree on every point. All throughout its history, the Catholic Church has had various theologians toss ideas back and forth to try to come to agreement. Often, there was NO unanimity but majority rules. One church father revered in one century becomes a heretic in the next. One Pope proclaiming dogma gets contradicted by the next one and that one gets overruled later. I know how dearly Catholics want to hold onto that equilibrium and believe it is all true whatever they are told, but declaring herself the One, True Church did not prevent Rome from falling into debauchery and excess. Even the current homosexual/pedophile scandal is nothing new. It's been going on for well over a thousand years if not longer.
Where we know who are the true body of Christ, his bride, is by their hearts and no one can see another's heart. That's something only God can do, so He knows his own and he couldn't care less what sign is posted outside a believer's house of worship. The true bride will show herself by her fruits, the fruits of the Holy Spirit. The "authentic" teachings of Jesus ARE found in Holy Scripture. That's why He gave it to us! It alone is the only objective and authoritative source we have for knowing what is or isn't truth. On the basic doctrine of our salvation, it is crystal clear that we are saved by grace THROUGH faith in Jesus Christ and NOT of our own works so that we cannot boast. Jesus did it ALL. He redeemed us by his precious blood shed upon the cross at Calvary so that the sin debt of the world would be paid IN FULL. It is only man-made religions that add onto that simple plan of salvation. Is it important to know about the nature of our God and how he has worked and will work in our world and lives? Sure, but it doesn't affect our salvation. That thief next to Jesus on the cross didn't need to know about the Trinity to be saved. He didn't have to get down from his cruel cross to get baptized "properly" to be saved. He didn't have to take a new members class to be saved or be able to quote Bible verses. He didn't even have to receive the Eucharist to be saved. But Jesus said, "Today, you will be with me in Paradise.".
We have the writings of the Apostles and their direct disciples that explain the doctrines Christians need to know to be good Christians and live lives that honor and glorify God. He certainly wants us to. He gave us the Holy Spirit to be our guarantee of eternal life and to lead us into all truth. He gave to the believers within each local church pastors and teachers and evangelists to equip and edify the saints to help us be all that God desires for us. He didn't leave us without the Comforter - HIS presence with us for all time. We CAN know we have everlasting life right now, because we believe on the Lord Jesus Christ and his grace is sufficient for us. What a wonderful plan God has for each one of us! It starts with being born again into HIS family by grace through faith in Christ. That is the simple - deceptively simple for some - plan of salvation.