When God wants a certain work done He calls somebody out from among the ranks of men and sets him to do that work.
The fitting for the performance may be a slow process, as in the case of Jesus of Nazareth, who was thirty years preparing for his three years' public ministration; or it maybe in a moment, in the twinkling of an eye, as in the case of Saul of Tarsus.
The slower the fire of preparation the more mighty the work it would seem, if the difference between the times of the preparation of these two, and the difference between the accomplishments of each, are typical of all.