1 John 3:12

Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous.

Ver. 12. Who was of that wicked one] Tertullian calleth Cain the devil's patriarch. Cain is dead, saith another, but I could wish that he did not still live in his heirs and executors, Qui clavam eius sanguine Abelis rubentem, ut rem sacram circumferunt, adorant et venerantur, who bear about and make use of Cain's club, to knock on the head God's righteous Abels. (Bucholcer.)

And slew his brother] Gr. εσφαξε cut his throat. Acerbissima sunt odia (ut ita nominem) Theologica, saith one. These divinity hatreds are most deadly. Such fratricides were Alphonsus Diazius, and Charles, king of France, stirred up by Pope Urban to kill his brother Manford, king of Sicily.

Because his own works, &c.] The old enmity, Genesis 3:15. So Numbers 22:3,4. Moab was irked because of Israel, or did fret and vex at them, as Exodus 1:12, yet they were allied, and passed by them in peace, and, by the slaughter of the Amorites, freed them from evil neighbours which had taken away part of their land, and might do more, as one hath well observed.