The invisible nature of God does not follow from anything John has said before and is introduced here only to allow him to expound further aspects of love’s great benefits and power. We worship the invisible God who is outside and beyond his creation, and therefore man is forbidden to make any image or likeness of God.
Since God is invisible to mortal man, it is an error for any to claim to have direct access to him. There is no technique or religious practice that can make the invisible God visible, for while we are in the body God can only be known by faith. John shows us here a better way in which we draw close to God – through the exercise of brotherly love.
By the exercise of love we are brought closer to God than to any human being, for no human being can be said to dwell in us. We may have closer fellowship with the Lord even than with one another, and the fellowship that we have with one another is a result of our fellowship with God. We consciously enjoy the exercise of love which we know he too loves to exercise.
Was not Christ the image of the invisible God and did he not come to make God known? He came, but many looked upon him and saw a mere man; he was known only to the eye of faith for his divine nature remained invisible.