Yes, I tell you that, from the blood of Abel down to the blood of Zechariah who perished between the altar and the House, it shall all be required from the present generation.
that all the innocent blood shed upon earth may come on you, from the blood of righteous Abel to the blood of Zechariah the son of Berechiah whom you murdered between the Sanctuary and the altar.
Through faith Abel offered to God a more acceptable sacrifice than Cain did, and through this faith he obtained testimony that he was righteous, God giving the testimony by accepting his gifts; and through it, though he is dead, he still speaks.
We are not to resemble Cain, who was a child of the Evil one and killed his own brother. And why did he kill him? Because his own actions were wicked and his brother's actions righteous.