By faith Abel offered God a more acceptable sacrifice than Cain, through which he was commended as a righteous man, when God spoke well of his gifts. And through faith he still speaks, even though he is dead.

and 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.

Woe to them! For they have gone the way of Cain, and for the sake of gain they have rushed headlong into the Balaam's error, and perished in Korah's rebellion.