Beloved, if God so loved us, we also ought to love one another. (12) No one has seen God at any time. If we love one another, God abides in us, and His love has been perfected in us. (13) By this we know that we abide in Him, and He in us, because He has given us of His Spirit. (14) And we have seen and testify that the Father has sent the Son as Savior of the world. (15) Whoever confesses that Jesus is the Son of God, God abides in him and he in God. (16) 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.
The first sentence of today’s verses, written by the apostle John, refers to the great love God had for us in sending His Son to save us from sin. God set the example and Christ proved His love and our resulting love for one another is not just a nice thing. It is, in faith, not just who we are now, but an obligation.
John tells us that no man has seen God – meaning we have not beheld Him with our eyes, but have experienced His essence through the love He has shown us. We have not seen the wind either but see it’s effects. At the moment of faith in Christ Jesus we are reborn – transformed into new men and women and this rebirth is sealed by the now indwelling Spirit of God. Since the essence of God is love and this love is conferred on man by the indwelling Spirit, by faith God dwells in us. Wherever God abides, love is – so love is necessarily connected with faith in Christ Jesus. John is telling us in our verses today that faith in Jesus rests on historic apostolic witness to the person of Christ Jesus; the fulfillment of all the Old Testament prophecies – they saw the miracles, heard the teaching of Christ and were eyewitness to the Resurrection
John is NOT saying that the way to abide in God is to confess faith in Christ and love one another, he is saying that GOD HAS INITIATED this reconciliation and our transformation by faith and the resulting love for one another is EVIDENCE that we are saved. Salvation is of the Lord not of man.