Charles Ellicott Commentary Proverbs 20:21

"An inheritance [may be] gotten hastily at the beginning; But the end thereof shall not be blessed." — Proverbs 20:21 (ASV)

The end thereof shall not be blessed.— Compare to Proverbs 28:20: the evil means by which he acquired the possession will ultimately be visited upon him. Thus Jacob was punished severely for the selfishness by which he gained the birthright, and for the fraud by which he obtained the blessing belonging to his brother.