11 For this is the message that you have heard from the beginning, that we should love one another. 12 We should 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 3:11-18 English Standard Version
I want to, with brevity, extrapolate for us a lesson from this idea of murder. The Bible Exposition Commentary by Warren W. Wiersbe says, “Murder, of course, is the lowest level on which one may live in relationship to someone else. It is the level on which Satan himself exists. The devil was a murderer from the beginning of his fallen career (John 8:44), but Christians have heard, from the beginning of their experience, that they are to “love one another.” John emphasizes origins: “Go back to the beginning.” If our spiritual experience originates with the Father, we must love one another. But if it originates with Satan, we will hate one another. “Let that therefore abide in you, which ye have heard from the beginning” (1 John 2:24).”[1]
[1] Warren W. Wiersbe, The Bible Exposition Commentary, vol. 2 (Wheaton, IL: Victor Books, 1996), 509.