“If we love one another, God abides in us, and His love will be perfected in us. In this know we that we abide in Him, and He in us, because He has given us of His Spirit. And we have seen and are witnesses that the Father sent the Son to be the Saviour ofthe world. Whosoever shall confess that Jesus is the Son of God, God abides in him, and he in God. And we have known and believed the love that God has to us. God is love; and he that abides in love abides in God, and God abides in him.”
Source: Homilies on the First Epistle of John (New Advent)