Christianity is not based on what Jesus taught, but rather on Who He is and What He accomplished. This categorizes His teachings alone as absolute truth. The preaching of these truths by His followers has touched the world down through all ages. What Jesus touches, He changes and that always for the betterment of mankind. Despair gives way to encouragement.
Sin gives way to holiness.
Despondency gives way a blessed hope. He Who gave His life gives life to those who believe in Him. There can be no Christian view without Christ. By this, I mean the anticipation of His birth. Fulfilled prophecy is a unique fact of Christianity.