No man is the absolute keeper of his brother, so as to be responsible for his safety when he is not present. This is what Cain means to insinuate. But every man is his brother's keeper so far that he is not himself to lay the hand of violence on him, nor suffer another to do so if he can hinder it. This sort of keeping the Almighty has a right to demand of every one - the first part of it on the ground of mere justice, the second on that of love. But Cain's reply betrays a desperate resort to falsehood, a total estrangement of feeling, a quenching of brotherly love, a predominence of that selfishness which freezes affection and kindles hatred. This is the way of Cain.
