It is very easy for modern historians and liberal theologians to debate the authenticity of God's Holy word. If there is a part of the scripture that they do not want to believe, they will find a way to dismiss it. I personally feel that God is capable of keeping His words for us intact through all of history and I believe He did that in the form of the Holy Bible as we have it in print today. My answer to your question is, find a copy of the Holy Bible, red letter edition. In the gospels of Matthew, Mark, Luke and John, you will find a large amount of text printed in red. Those are the words attributed to Jesus. There will also be a few quotes in Acts and Revelation.