8 Hence, they who blame, and call by the name of sedition, this steadfastness of attitude in the choice of duty have not rightly apprehended the force and nature of true law. We are speaking of matters widely known, and which We have before now more than once fully explained. Law is of its very essence a mandate of right reason, proclaimed by a properly constituted authority, for the common good. But true and legitimate authority is void of sanction, unless it proceed from God, the supreme Ruler and Lord of all. The Almighty alone can commit power to a man over his fellow men;(5) nor may that be accounted as right reason which is in disaccord with truth and with divine reason; nor that held to be true good which is repugnant to the supreme and unchangeable good, or that wrests aside and draws away the wills of men from the charity of God.
Source: Sapientiae Christianae (Vatican.va)