“And we have known and believed the love that God has for us. God is love, and he who abides in love abides in God, and God in him.”
This verse summarizes 3:24-4:16 — intimate fellowship with God is impossible without love for fellow Christians.
And we have known and believed the love that God has for us.
Notice the order of “have known and believed.” We must first hear the gospel before we can believe it. By the same token, we must know God’s love before we can believe God’s love for us. Those who experience God’s love come to have confidence in His love. Confidence in God’s love comes from knowledge about His love.
God is love,
John parlays his discourse of the doctrine of Christ into a discussion of God’s love and Christian love. This is a logical deduction from the nature of God, from His orientation to love. God is unconditional, incomprehensible, incomparable love. We see this clearly in the sacrifice of His Son for our sins.
John previously used the phrase “God is love” in verse 8 to make a case for loving fellow Christians. He reiterates the truth that “God is love” here to show the close connection between fellowship with God and loving fellow believers. Only by abiding in God’s love can true fellowship with Him be made real. Both verses connect to the idea that God sent His Son into the world (4:8,9 and 4:14,16). God reveals His love through Jesus Christ. God sending His Son is proof of His love for us and the execution of that love in us.
and he who abides in love abides in God,
There is a close correlation between loving Christians and fellowship with God. Since God in His essence is love, where God is, love is. This is the work of the Holy Spirit in us.
and God in him
God’s love operates within the sphere of the believer. John is confident that God’s love works in Christians, as they love one another. If God dwells in a believer, love dwells there too. The doctrine of God indwelling the believer also implies love indwelling the believer. There is an indwelling love that God imparts to every believer.
There is great reciprocity between God’s love and the loving believer.
Where God’s is, His love is. Love always flows from fellowship with God. God works in Christians as they love one another. We cannot fellowship with God if we harbor malice toward fellow Christians.
All Christians are indwelt by God, so all believers are indwelt by love. God indwelling the believer is tied inseparably to the confession of Christ as God, as the Son of God. A domino effect occurs from belief – belief results in God’s indwelling the believer, and God’s indwelling produces dynamic love in the Christian.
We must first know the love of God before we can believe the love of God. This is another way of saying that when we experience the love of God, we know something about how to love others.
It is possible by unbelief to block in advance, appreciation of God’s love. Knowledge and belief act and react with each other. Any truth not applied to experience is worthless. God’s Word must be known and believed to be effective. Belief without knowledge is unadulterated gullibility.