Adam Clarke on Genesis 4:12

A fugitive and a vagabond shalt thou be - Thou shalt be expelled from the presence of God, and from thy family connections, and shalt have no fixed secure residence in any place. The Septuagint render this στενων και τρεμων εση, thou shalt be groaning and trembling upon the earth - the horror of thy crime shall ever haunt thee, and thou shalt never have any well-grounded hope that God will remit the punishment thou deservest. No state out of endless perdition can be considered more awful than this.