[An Evangelist should] be always careful that he is occupied with the truth ... the central truth being CHRIST CRUCIFIED. The Evangel, or the Gospel, is a message of Good Tidings. The Evangelist is the one to proclaim that message, the herald of glad news of great joy. He must be possessed with intense love for the message, as well as compassion for the souls of men, knowing at heart that God has entrusted him as an ambassador with the message of Peace to a rebellious world, and with the prescription of healing to the dying millions ... This declaration of Salvation by grace through faith in the Lord Jesus is the function of the Evangelist, so, in order to be prosperous, he must understand his message, as well as be equipped to proclaim it.
D.P. Williams, The Work of An Evangelist (Penygroes: The Apostolic Church, 1928), 15