By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained the testimony that he was righteous, God bearing witness to his gifts: and by it, though dead, he yet speaketh.

for this is the injunction which ye heard from the beginning, that we should love one another: not as Cain who was of the evil one, and slew his brother;

Wo unto them; for they have gone in the way of Cain, and been carried away by Balaam's error, the love of lucre, and perished as in the contradiction of Korah.