Book 1 · Section 74

(74) What is the meaning of Cain, when he says, "Everyone who shall find me will kill me:" when there was scarcely another human being in the world except his parents? (#Ge 4:14). In the first place he might have received injury from the parts of the world which indeed were made for the advantage of the good and that they might partake of them, but which nevertheless, derived from the wicked no slight degree of revenge. In the second place it may be that he said this, because he was apprehensive of injury from beasts, and reptiles; for nature has brought forth these animals with the express object of their being instruments of vengeance on the wicked. In the third place, some people may imagine that he is speaking with reference to his parents, on whom he had inflicted an unprecedented sorrow, and the first evil which had happened to them, before they knew what death was.