"This Life appeared and we’ve seen and confirmed, and now we’re telling you about the Eternal Life Who is from the Father and appeared to us. We declare to you the very One we’ve seen and heard so that you can have communion with us. And this communion of ours is with the Father and His Son, Jesus Christ.” – I John 1:2-3
There is another aspect of fellowship here which John is drawing us into. It is a communion, not only between himself and the Church, but with God the Father and Jesus Christ. And this is made possible because of Jesus and the things which John proclaims about him. The Revelator wastes no time, but cuts straight away to the testament, to the heart of it all – this Life (that is, Jesus) appeared, was made manifest. The Life was with God the Father but came to be among us, bridging the gap between man and eternity, earth and glory. This is exactly why Jesus came; because we were once close to the Father, He once walked with man in the cool of the day, but sin ruined all that. So Jesus came to renew our relationship, to redeem it, to conquer death so that we may live. And true life is in Christ, to be in fellowship with the Father and the Son, as we were meant to be all along.