Christians who specialize in evangelism are often known as evangelists, whether they are in their home communities or living as missionaries in the field, although some Christian traditions refer to such people as missionaries in either case. Some Christian traditions consider evangelists to be in a leadership position; they may be found preaching to large meetings or in governance roles.
Christian groups who encourage evangelism are sometimes known as evangelistic or evangelist. The scriptures do not use the word evangelism, but evangelist is used in (the translations of) Acts 21:8, Ephesians 4:11, and 2 Timothy 4:5.
The word evangelist comes from the Koine Greek word εὐαγγέλιον (transliterated as euangelion) via Latinised evangelium as used in the canonical titles of the Four Gospels, authored by (or attributed to) Matthew, Mark, Luke, and John (also known as the Four Evangelists). The Greek word εὐαγγέλιον originally meant a reward given to the messenger for good news (εὔ = "good", ἀγγέλλω = "I bring a message"; the word "angel" comes from the same root) and later "good news" itself.
The verb form of euangelion, (translated as "evangelism"), occurs rarely in older Greek literature outside the New Testament, making its meaning more difficult to ascertain. Parallel texts of the Gospels of Luke and Mark reveal a synonymous relationship between the verb euangelizo (εὑαγγελίζω) and a Greek verb kerusso (κηρύσσω), which means "to proclaim".
Christians would clearly distinguish between evangelism and proselytism, with the latter being viewed as unethical because it involves the abuse of people’s freedom and the distortion of the gospel of grace by means of coercion, deception, manipulation, and exploitation. Within Christianity, the label of ‘proselytism’ generally arises when one group does not approve of the missional activities of another, particularly when one group is losing members or the potential exists for this to occur.