This apostolic letter speaks authoritatively about the truth of the incarnation-a message his doubting readers needed after hearing false teachers deny the full divinity and humanity of Christ. It reaffirms the core of Christianity, saying that either we exhibit the sound doctrine, obedience, and love that characterize all Christians, or else we are not true Christians. When all the basics of faith are in operation, we not only know joy but can live a holy life and be assured of salvation (3:19, 24)-even though we are still far from perfect (1:9). This assurance comes especially as we find ourselves learning to "love one another" as brothers and sisters in Christ (4:7-8). This general letter to congregations across Asia Minor (now Turkey) was probably written by the apostle John in the late first century a.d.