Jesus was put on earth not to write the teachings, but to teach the writers. In essence Jesus was an extension of god the fathers being and influence. This is supported by the fact that Mary experienced a miracle birth through the holy spirit. God presented the world with the opportunity to experience and record the walk of a truly holy man, one that was not born into sin nor did he ever commit sin. What this did was basically show the children of god a physical example of what to strive for in their worship of god. So, since gods divine presence was instilled in Jesus, it also makes Jesus a divine/holy entity by association. If god had intended Jesus to contribute to the bible and bestow upon us written lessons, then he (god) could have accomplished the same thing by sending down the commandments version 2.0 . Instead god knew that Jesus would have a much larger impact on people by demonstrating the love, understanding, and power of god first had rather than just writing about it. Its simply the method of "actions speak louder than words" rather than "do it because i said so". Also you must remember that Jesus was a divine creature because of the method of his conception through the holy spirit. Jesus had the full power of god behind him, because Jesus was in a sense god. At any time god could have enabled Jesus to overtake the worlds empires and claim the entire earth for his glory, but that is just the thing, there is no glory in forcing your servants to serve you, but there is glory in convincing men with free will to serve you. If Jesus were to do any more on earth than display gods love, and power then it would have been no different than god coming down and saying hey i'm god so you better follow me, thus making the choice of servitude an easy one, thus ruining the idea of faith, thus robing god of his desired glory.