1 John 3:10-12

Revised Standard Version Catholic Edition

¹⁰ By this it may be seen who are the children of God, and who are the children of the devil: whoever does not do right is not of God, nor he who does not love his brother.

Love One Another

¹¹ For this is the message which you have heard from the beginning, that we should love one another, ¹² and not be like Cain who was of the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother’s righteous.