In the physical world we find these stages. First one comes to combat evil, often failing. Then another comes who moves the hearts and minds of man, and finally the third person becomes the leader in the righteous cause.
On the mental plane we have the one who exhorts but does not move; this is the reformer, although some reformers are very successful in moving the emotions of man, but they do not always touch the mind or heart. The prophet is of another character, who places the seed of righteousness in the mind and heart that it may fructify. The movement that he has founded becomes organized, often as a religion, and the priest is the leader in religion.
From another point of view, the reformer helps to clear away emotional rubbish, the prophet helps to keep the mind pure, and the priest helps to preserve the purity in the heart after it is once attained.