“If your brother or sister does something wrong to you, go and tell that person what he did wrong. Do this alone with that person. If that person listens to you, then you have helped that person to be your brother again.
But the person who hates his brother or sister is in darkness. He lives in darkness. That person does not know where he is going. Why? Because the darkness has made him blind.
A person says, “I am in the light. {\cf2\super [4]} ” But if that person hates his brother or sister \{in Christ\}, then he is still in the darkness (sin).
So we can see who God’s children are. Also, we can know who the children of the devil are. The people who don’t do what is right are not children of God. And the person who does not love his brothers and sisters \{in Christ\} is not a child of God.
Don’t be like Cain. {\cf2\super [10]} Cain belonged to the Evil One (the devil). Cain killed his brother \{Abel {\cf2\super [11]} \}. But why did Cain kill his brother? Because the things Cain did were evil, and the things his brother \{Abel\} did were good.