Since parts of the New Testament were first delivered orally, how do we know if we have a 100% accurate rendition of the original writings that were spoken by the Holy Spirit? I've heard that through oral teachings, details could be lost and distorted. For example, someone may deliver a story to 20 people of a person sitting on a well doing something spectacular, but then some of the 20 people tell other groups of people that the person doing something spectacular was standing on a rock rather than sitting on a well, and then years later that story's details could be distorted even more whereas the person could be laying in the mud in another city doing something spectacular. I am curious to know how the Bible passes this test of oral transmission and possible errors in the words that we have in our current canonized Bible. Do we have the exact words that Jesus and the Apostles spoke and how do we get past this oral transmission issue?
Because the ones who wrote the New Testament were the same people who gave the original oral teachings as well.
"That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, concerning the Word of life -- the life was manifested, and we have seen, and bear witness, and declare to you that eternal life which was with the Father and was manifested to us -- that which we have seen and heard we declare to you, that you also may have fellowship with us; and truly our fellowship is with the Father and with His Son Jesus Christ. And these things we write to you that your joy may be full." (I John 1:1-4).
"Yes, I think it is right, as long as I am in this tent, to stir you up by reminding you, knowing that shortly I must put off my tent, just as our Lord Jesus Christ showed me. Moreover I will be careful to ensure that you always have a reminder of these things after my decease" (II Peter 1:13-15).
In addition, these men were guided by the Holy Spirit to remember and accurately write what God taught them.
"But as it is written: Eye has not seen, nor ear heard, Nor have entered into the heart of man The things which God has prepared for those who love Him." But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God. For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God. Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God. These things we also speak, not in words which man's wisdom teaches but which the Holy Spirit teaches, comparing spiritual things with spiritual" (I Corinthians 2:9-13).