1 John 3:11-12, 23

For this is the message which ye heard from the beginning, that we should love one another: not as Cain was of the evil one, and slew his brother. And wherefore slew he him? Because his works were evil, and his brother’s righteous.

And this is his commandment, that we should believe in the name of his Son Jesus Christ, and love one another, even as he gave us commandment.