Theophilus to Autolycus

When, then, Adam knew Eve his wife, she conceived and bare a son, whose name was Cain; and she said, “I have gotten a man from God.” And yet again she bare a second son, whose name was Abel, “who began to be a keeper of sheep, but Cain tilled the ground.” Their history receives a very full narration, yea, even a detailed explanation: wherefore the book itself, which is entitled “The Genesis of the World,” can more accurately inform those who are anxious to learn their story.

When, then, Satan saw Adam and his wife not only still living, but also begetting children— being carried away with spite because he had not succeeded in putting them to death—when he saw that Abel was well-pleasing to God, he wrought upon the heart of his brother called Cain, and caused him to kill his brother Abel. And thus did death get a beginning in this world, to find its way into every race of man, even to this day. But God, being pitiful, and wishing to afford to Cain, as to Adam, an opportunity of repentance and confession, said, “Where is Abel your brother?”

But Cain answered God contumaciously, saying, “I know not; am I my brother's keeper?” God, being thus made angry with him, said, “What have you done? The voice of your brother's blood cries to me from the earth, which opened her mouth to receive your brother's blood from your hand. Groaning and trembling shall you be on the earth.” From that time the earth, through fear, no longer receives human blood, no, nor the blood of any animal; by which it appears that it is not the cause [of death], but man, who transgressed.