Genesis 4:12

When thou tillest the ground, it shall not henceforth yield unto thee her strength. A fugitive and a vagabond shalt thou be in the earth. The irrational creature suffers and groans on account of the sin of man. The earth refuses to yield a crop to the murderer, no matter how hard he should attempt to coax it by the most careful tilling. A feeling of inward quaking, of trembling, of restlessness, would result in Cain's outward fleeing, in a roving without home and without definite relationships. To this day this is the mark of the murderer, for his conscience will give him no rest, but drives him from one city to another, from one country to the next.