When Jesus said, I am the way, the truth, and the life: no man cometh to the Father, but by me. What was he really saying?
"Jesus said to him, "I am the way, the truth, and the life. No one comes to the Father except through Me" (John 14:6).
Peter states basically the same thing at a later time, "Let it be known to you all, and to all the people of Israel, that by the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead, by Him this man stands here before you whole. This is the 'stone which was rejected by you builders, which has become the chief cornerstone.' Nor is there salvation in any other, for there is no other name under heaven given among men by which we must be saved" (Acts 4:10-12).
The point is that there is only one route to heaven, there is only one way to approach the Father, there is only one standard of living acceptable to God.
That there is only one way is illustrated by Jesus. "Enter by the narrow gate; for wide is the gate and broad is the way that leads to destruction, and there are many who go in by it. Because narrow is the gate and difficult is the way which leads to life, and there are few who find it" (Matthew 7:13-14). Paul later points out in a list of "ones" that there is only one faith (Ephesians 4:6-9); that is, there is only one system of belief established by God. Jesus is stating that you can't go off and find your own way to heaven. There is only one way and that way is found by following Jesus (John 10:9). "For through Him we both have access by one Spirit to the Father" (Ephesians 2:18).
Jesus is the truth because his teachings are truth. At the beginning of John, Jesus is called the Word. "In the beginning was the Word, and the Word was with God, and the Word was God" (John 1:1). A bit later John states, "And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth" (John 1:14). This takes on special significance when we read Jesus' statement, "Sanctify them by Your truth. Your word is truth" (John 17:17). But Jesus is the Word; therefore, Jesus is the truth.
And by life, Jesus is stating that only through him can eternal life be granted. "In Him was life, and the life was the light of men" (John 1:4). Later Jesus stated, "Most assuredly, I say to you, he who hears My word and believes in Him who sent Me has everlasting life, and shall not come into judgment, but has passed from death into life. Most assuredly, I say to you, the hour is coming, and now is, when the dead will hear the voice of the Son of God; and those who hear will live. For as the Father has life in Himself, so He has granted the Son to have life in Himself, and has given Him authority to execute judgment also, because He is the Son of Man" (John 5:24-27).
If you want to be saved from your sins, there is only one way -- through the teachings of Jesus.