Genesis 4:9 - Coke's Commentary on the Holy Bible

I know not: am I my brother's keeper?— There is no wonder, that he, who from such vile motives could murder his brother, because his own works were evil, and his brother's righteous, 1 John 3:12 should, with an impudent sullenness, give the lie to his Maker. See the dreadful effects of the fall immediately indicating themselves, to display which, was probably one great reason of recording this history. Again, Abel, as Calmet observes, unjustly murdered by his eldest brother, admirably denotes the violent death of the Lord Jesus Christ by the hands of the Jews. St. Paul says, that the blood of Jesus speaketh better things than that of Abel, Hebrews 12:24.