Barnes New Testament Notes

Verse 12. Not as Cain. Not manifesting the spirit which Cain did. His was a most remarkable and striking instance of a want of love to a brother, and the case was well adapted to illustrate the propriety of the duty which the apostle is enjoining. See Ge 4:4-8.

Who was of that wicked one. Of the devil; that is, he was under his influence, and acted from his instigation.

And wherefore slew he him? Because his own works were evil, and his brother's righteous. He acted under the influence of envy. He was dissatisfied that his own offering was not accepted, and that his brother's was. The apostle seems desirous to guard those to whom he wrote against the indulgence of any feelings that were the opposite of love; from anything like envy toward more highly favoured brethren, by showing to what this would lead if fairly acted out, as in the case of Cain. A large part of the crimes of the earth have been caused, as in the murder of Abel, by the want of brotherly love. Nothing but love would be necessary to put an end to the crimes, and consequently to a large part of the misery, of the world.

{b} "Cain, who" Ge 4:4-8