Did you skip over the part in my response where I said:
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.
So, no, not all will be saved because not all will BELIEVE. I don't accept "universal salvation", do you? Jesus said the way to heaven was narrow and FEW would find it. Any religion, whose claim to fame is the enormous total of their membership, doesn't sound like the way Jesus spoke of. The reason to teach and evangelize the world, according to Jesus' command is so that the world would hear of the coming of the savior and all those who diligently seek for the truth will know. After one believes and is saved, their walk with Christ, through the indwelling Holy Spirit, is used by God to reach a lost and dying world with the good news of the Gospel. As I said, we learn to live to please God and honor him so that the world will be drawn to Christ. Rather than thinking our works and deeds are what "merit" or "earn" our salvation, we are told that it is by God's GRACE alone that we can be saved. It is faith in Christ, believing in him and what he has done for us, that saves. Pure grace - undeserved, unmerited, unearned.
As to the "authentic" teachings of Jesus, if they were not included in the Scriptures, then they are not binding on a Christian, they don't influence what it takes to be saved. No one denies that Jesus did many things or even said many things not recorded in Scripture, because Scripture SAYS that, but John said what he DID write down was so we would believe and have eternal life. Whatever anyone adds to Scripture, insisting Jesus really DID say or the Apostles really did say, have no objective proof. Especially we must question anything that would contradict what is in Scripture. If these guidelines are lacking in your church, then you should know you might be following man-made doctrine that has no assurance of coming from God. There's PLENTY of that going around.
We are of course saved by God’s grace and mercy provided we follow His Teachings. His teachings are not confined to only the text found in scripture. It was left to the early Church Fathers to sort out what books, writings, and texts guided by the Holy Spirit to include in the book we called the Bible. But interpreting its text and how it was understood was left to His disciples to be taught to all nations as ONE Truth and for this He established His Church and gave to Peter and his successors the keys to the Kingdom of heaven. We each can’t have our own interpretations otherwise we become a Tower of Babel.
For example, on the Road to Emmaus, the disciples recognized our Lord only when He broke the bread. The apostles and their successors found this to be as one more experience and what was understood by all His followers at the time to be the institution of the Holy Eucharist.
Now you may disagree as well as would others. But those who disagreed before like Cardinal Newman and pre-eminet U.S. Lutheran theologian Fr. Neuhaus on deeper scholarship and understanding came to agree on this interpretation and being true to their conscience they all converted to Catholicism.
Just look around and see the utter disarray among the thousands of Christian sects purporting to interpret scripture from novice “prosperity gospel” fools like Joel Osteen and “socialist” Rev. Wright to established sects like the gay clergy marriage approving Church of England, Lutherans, Episcopalians, and the Scottish rites. Then of course, we have the Black Churches (AME), the Korean Churches, and the individuals from kool-aid Rev. Jim Jones to rapture nuts like Rev. David Koresh.