2 Samuel 12:31
And he brought forth the people that were therein, and put them under saws, and under harrows of iron, and under axes of iron, and made them pass through the brickkiln: and thus did he unto all the cities of the children of Ammon. So David and all the people returned unto Jerusalem.
This verse stands within the history of David's fall in the matter of Uriah. It belongs to that dark chapter in which the king, though still holding the position and authority God had given him, had departed from God. For that time he had become an agent of Satan, turning God-given authority to a wrongful use.
He used that authority to claim an obedience that would imperil the soul, by commanding what was contrary to God's law. Joab, in carrying out such a command, transgressed God's law by obeying the king rather than God. His course revealed that his allegiance was to the king rather than to God. Power bestowed by God is to be exercised only in harmony with divine law. To obey a human command that contradicts God's law is itself sin.