Expositor's Bible Commentary Commentary 1 John 4:16

"And we know and have believed the love which God hath in us. God is love; and he that abideth in love abideth in God, and God abideth in him." — 1 John 4:16 (ASV)

The same combination of knowing and believing is found in Peter’s confession of Jesus in Jn 6:69, except that there the order of “believe” and “know” is reversed. The fact is that faith may lead to knowledge and knowledge may lead to faith. Here knowledge of God’s love necessarily precedes the ability to “rely” on that love. The sequence of thought is this: First, we must know and rely on the fact that God loves us. Second, we come to realize through relying on his love (or having faith in his Son—the meaning is the same) that in his very nature God is love. Third, we discover that to live in God means to live in love.

The fellowship we have with the Father and with the Son (1:3) is perceived as nothing other than a fellowship of love.