Cain was stronger than Abel because Cain was a farmer, a settler, while Abel was a shepherd, a nomad. Cain rose and slew his brother because he was the stronger; he had land-attachments, and he fought for them. Abel, the nomad, was “weak” and knew not how to defend himself, for he had no “mental bonds” that would incite him to an act of defense. And the most fitting punishment for Cain was for him to become a nomad, wandering the earth, restless and derelict.—Soloveichik.