Sometimes when I read a passage, I just want to copy and paste everything here. The words are so encouraging, striking or beautiful. The first two verses are just great. They remind us of our status as children of God, because of his great love. Then it speaks to what we will become when Jesus returns; we will become like him.
John then goes on to remind us that we are not to continue sinning because we are in Christ. Sin is of the devil, for he is the original sinner. (Not Adam and Eve!) But we are born of God, being his children, so we no longer have sin in us. Again, this holds in tension the now and not-yet aspect of the Gospel. However, transformative change is possible and God does work in our hearts.
We are also to love our brothers and sisters. This is not because of how we are treated or because those around it deserve it. In fact, we should expect to be hated. We love despite this and because of God’s great love.
Loving others is a command from Christ and is in obedience to God. Again, it brings together the two-fold aspect of the greatest commandment: love the Lord your God and love your neighbour. You cannot do one without the other.