No one has ever seen God. John certainly taking a bend on a theological and biblical understanding of God's presence. {God has constantly and consistently made God's presence known, just not through a physical construct, i.e. the burning bush, the pillars of cloud and fire, the whirlwind. Also, Job 42:5 explains Job's predicament of no longer hearing about God but experiencing God face to face.}
John intends for us to know that love was perfected in Christ, God's outpouring of love by sending God's son into the world to bridge the gap of sin that separates us from God. Hence, God is love. But here John insists that the community, as the body of Christ, brings love to fulfillment when we show love to each other and the world God made.
Love comes not from the best of the human spirit but it comes from God. The fulfillment of love experienced by loving others and having been loved by others in community brings us as a community into the fullness of God's love. This is a tangible sign of God's presence, much like the burning bush, the pillar of cloud and fire, whirlwinds and Job's experience of God.