This is how we know that we live in him and he in us: He has given us of his Spirit. And we have seen and testify that the Father has sent his Son to be the Savior of the world. If anyone acknowledges that Jesus is the Son of God, God lives in them and they in God. And so we know and rely on the love God has for us.
God is love. Whoever lives in love lives in God, and God in them. This is how love is made complete among us so that we will have confidence on the day of judgment: In this world we are like Jesus. There is no fear in love. But perfect love drives out fear, because fear has to do with punishment. The one who fears is not made perfect in love.
We love because he first loved us. Whoever claims to love God yet hates a brother or sister is a liar. For whoever does not love their brother and sister, whom they have seen, cannot love God, whom they have not seen. And he has given us this command: Anyone who loves God must also love their brother and sister.