1 John 3:11 in the King James Version
For this is the message that ye heard from the beginning, that we should love one another.
Context
10 In this the children of God are revealed, and the children of the devil. Whoever doesn’t do righteousness is not of God, neither is he who doesn’t love his brother.
11 For this is the message which you heard from the beginning, that we should love one another—
12 unlike Cain, who was of the evil one and killed his brother. Why did he kill him? Because his deeds were evil, and his brother’s righteous.