Jesus did bring a "new" doctrine, that is, a different teaching than the Pharisees. Jesus taught the Kingdom of God is coming soon and proved He was the Messiah by miracles that only the God can do. However, Jesus didn't teach the qualification for a preacher and deacon. Jesus said, only in Mark 16:15-18 that those with Holy Spirit will not be poisoned and pickup snakes, heal people, and cast out demons. The Apostle Paul told of the gifts of the Spirits and the divisions of Church hierarchy. that is , some are preachers, teachers, prophets, evangelists, and Apostles. Without Paul's letters we wouldn't have the clarification of all Jesus taught; the age of Grace without works.