The order of authority derives from God, as the Apostle says [ in Romans 13:1-7]. For this reason, the duty of obedience is, for the Christian, a consequence of this derivation of authority from God, and ceases when that ceases. But, as we have already said, authority may fail to derive from God for two reasons: either because of the way in which authority has been obtained, or in consequence of the use which is made of it. There are two ways in which the first may occur. Either because of a defect in the person, if he is unworthy; or because of some defect in the way itself by which power was acquired, if, for example, through violence, or simony or some other illegal method.