Dr. D. Martyn Lloyd-Jones (1919-1981) in his book Preaching and Preachers: The work of preaching is the highest and the greatest and the most glorious calling to which anyone can ever be called. If you want something in addition to that I would say without hesitation that the most urgent need in the Christian church today is true preaching; and as it is the greatest and most urgent need in the Church; it is obviously the great need of the world also.