13. The Almighty, therefore, has given the charge of the human race to two powers, the ecclesiastical and the civil, the one being set over divine, and the other over human, things. Each in its kind is supreme, each has fixed limits within which it is contained, limits which are defined by the nature and special object of the province of each, so that there is, we may say, an orbit traced out within which the action of each is brought into play by its own native right.
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There must, accordingly, exist between these two powers a certain orderly connection, which may be compared to the union of the soul and body in man. The nature and scope of that connection can be determined only, as We have laid down, by having regard to the nature of each power, and by taking account of the relative excellence and nobleness of their purpose. One of the two has for its proximate and chief object the well-being of this mortal life; the other, the everlasting joys of heaven. Whatever, therefore in things human is of a sacred character, whatever belongs either of its own nature or by reason of the end to which it is referred, to the salvation of souls, or to the worship of God, is subject to the power and judgment of the Church. Whatever is to be ranged under the civil and political order is rightly subject to the civil authority. Jesus Christ has Himself given command that what is Caesar's is to be rendered to Caesar, and that what belongs to God is to be rendered to God.