This is seen by the indisputable fact that the greatest and most influential preachers and teachers of the ages past, and the age in which we now live, have made constant use of it.The messages of the prophets were delivered in the open air. God's call to the prophet was: "Go, proclaim these words in the streets of the city" (Jer. 11:6). The sublime evangelical predictions of Isaiah; the mournful dirges of Jeremiah; the symbolical and picturesque...