The work of an evangelist is an essential part of expanding the borders and maintaining the well being of the Lord’s church.
The word evangelist in the New Testament means “a bringer of good tidings.” It comes from the word translated “gospel.” This describes the work he is to do.
Since the gospel is the good news message and the evangelist is the bringer of that message, an evangelist is a “gospelizer,” a bringer of the good news message of salvation by grace through faith in Christ Jesus. In the NT, this name refers to those who proclaimed salvation through Christ, who are not apostles (Acts 21:8; Eph. 4:11 and 2Tim. 4:5).
The term preacher refers to the same work. Vine's Word Study states that kerux is “a herald, it is used of the preacher of the gospel, it indicates the preacher as giving the proclamation” (1Tim. 2:7; 2Tim. 1:11; 2Peter 2:4,5). The verb form means “to be a herald, to officiate as a herald, to proclaim after the manner of a herald; always with a suggestion of formality, gravity, and on the authority which must be listened to and obeyed.” Kittels Theological Dictionary of the New Testament states, “usually it is transitive and describes the activity of the herald in the discharge of his office.” Since the leading quality demanded of a herald is that he should have a good voice, it always carries the primary meaning, “to cry out loud,” “to proclaim,” “to declare,” “to announce.” He goes on to say, It repeatedly has the sense of “call to something,” to summon someone to something.” “to appeal to, to implore someone.” What is declared by the herald can imply, “to offer,” “to forbid,” “to order” (2Tim. 4:1,2).
