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.

When thou tillest the ground,.... Which was the business he was brought up in and followed, Genesis 4:2

it shall not henceforth yield unto thee her strength; the earth had been cursed for Adam's sin, and was not so fruitful as in its original state; and now it was cursed again for Cain's sin; not the whole earth, but that part which belonged to Cain, and was cultivated by him; and so it must be supposed to be cursed, not only in the spot where he had been settled, but in every other place where he should come and occupy, and which through this additional curse became so barren that it did not yield such good fruits, and such an increase of it as before; it lost its native and vital juice, by which seed cast into it became not so fruitful, and did not increase; but instead of this, though much pains were taken to manure it, and much was sown, yet it brought forth little, at least but little to Cain, whatever it did to others; and therefore it is said, "shall not yield unto thee"; it would not turn much to his account, or yield much profit and increase to him, or bring forth much fruit; see Job 31:38

a fugitive and a vagabond shalt thou be in the earth; being obliged to quit his former habitation, and remove to a place at some distance from the house of his father Adam, which was near the garden of Eden, as Aben Ezra observes; and to wander about from place to place, having no quiet settlement in anyone place: the Septuagint render it "groaning and trembling"; the guilt of his sin lay heavy on his conscience, and filled him with such horror and terror that he was continually sighing and groaning, and was seized with such a tremor that he shook in all his limbs; so the Arabic writers {t} say, that he was trembling and quivering, and had a shaking in his head all the days of his life; and Aben Ezra observes, that there are some that say that the first of these words signifies to moan and lament; but it may be, it was not so much his sin, at least the evil of it, that he lamented, as the mischief that came by it, or the calamities and misfortunes it brought upon him.

{t} Patricides, apud Hottinger. Smegma Oriental. l. 1. c. 8. p. 223.