What does 1 John 1:3 mean?

John repeats his claim to eyewitness experience, from verse 1. These things John and others saw Jesus do, and which they heard Jesus teach, served as the basis for what they "proclaimed." The Greek word translated "proclaim" is apangellomen, which includes the idea of announcing or reporting. John could accurately teach about Jesus because he personally served with Him and had learned directly from the Lord.

The goal of John's teaching was shared fellowship. The idea of fellowship, from the Greek koinōnia, was an important concept in the New Testament (Acts 2:42). John noted the importance of fellowship with each other. And, he reminds the reader that we also have fellowship with both Christ and God the Father. This reflects the Great Commandment, found in the Gospels (Matthew 22:37–40), to love God and love your neighbor as yourself. A right relationship with God is seen as essential to right relationships with other people. Also important is John's emphasis of the connection of the Father and Son, a theme both in John's Gospel and the letter of 1 John.