1 John 3:12

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.

1 John 3:12 In-Context

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.
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.
13 Do not wonder, brethren, that the world hates you.
14 We know that we have passed out of death into life, because we love the brethren. He who does not love abides in death.
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.