Christianity has been an evangelistic faith since its beginning (see 691 [evangelism]), following the example of the apostles who could not keep the gospel (meaning “good news”) to themselves.
The book of Acts shows the faith spreading beyond its birthplace to the Samaritans, to the Roman province of Asia (what we today call Turkey), then jumping into another continent, to Macedonia and Greece, the gospel’s introduction to Europe.
Paul, the greatest missionary in the Bible, referred to himself and his coworkers as “ambassadors for Christ” (2 Cor. 5:20).