Elton Trueblood, the Quaker scholar, once compared evangelism to fire. Evangelism occurs, he said, when Christians are so ignited by their contact with Christ that they in turn set other fires. It is easy to determine when something is aflame. It ignites other material. Any fire that does not spread will eventually go out. A church without evangelism is a contradiction in terms, just as a fire that does not burn is a contradiction.

Christian Theology in Plain Language, p. 162