This is the message you heard from the beginning: We should love one another. Do not be like Cain, who belonged to the evil one and murdered his brother. And why did he murder him? Because his own actions were evil and his brother’s were righteous. Do not be surprised, my brothers, if the world hates you. We know that we have passed from death to life, because we love our brothers. Anyone who does not love remains in death. Anyone who hates his brother is a murderer, and you know that no murderer has eternal life in him.
This is how we know what love is: Jesus Christ laid down his life for us. And we ought to lay down our lives for our brothers. (1 John 3:11-16)