‘And we know and have believed the love which God has in us. God is love, and he who abides in love abides in God, and God abides in him.'
John wants there to be no doubt about the love that God has for His own, and how it affects us. We who are His, know and believe the love that God has in us. Note that it is in us as well as for us. We have come to the Saviour of the world and experienced and come to appreciate that love, and rejoice that it is within us, resulting in an outflowing of love for God and love for our brothers. We know further that God is holy love, and therefore that to abide in the love with which He surrounds us, which we enjoy in Christ, and which he has placed within us, is to abide in God Himself, and to know that God abides in us. We live within the sphere of the love of God, as well as in the light of God. We thus seek to live in purity.