Libertas §17

¹⁷ There are, indeed, some adherents of liberalism who do not subscribe to these opinions, which we have seen to be fearful in their enormity, openly opposed to the truth, and the cause of most terrible evils. Indeed, very many amongst them, compelled by the force of truth, do not hesitate to admit that such liberty is vicious, nay, is simple license, whenever intemperate in its claims, to the neglect of truth and justice; and therefore they would have liberty ruled and directed by right reason, and consequently subject to the natural law and to the divine eternal law. But here they think they may stop, holding that man as a free being is bound by no law of God except such as He makes known to us through our natural reason. In this they are plainly inconsistent. For if - as they must admit, and no one can rightly deny - the will of the Divine Law-giver is to be obeyed, because every man is under the power of God, and tends toward Him as his end, it follows that no one can assign limits to His legislative authority without failing in the obedience which is due. Indeed, if the human mind be so presumptuous as to define the nature and extent of God's rights and its own duties, reverence for the divine law will be apparent rather than real, and arbitrary judgment will prevail over the authority and providence of God. Man must, therefore, take his standard of a loyal and religious life from the eternal law; and from all and every one of those laws which God, in His infinite wisdom and power, has been pleased to enact, and to make known to us by such clear and unmistakable signs as to leave no room for doubt. And the more so because laws of this kind have the same origin, the same author, as the eternal law, are absolutely in accordance with right reason, and perfect the natural law. These laws it is that embody the government of God, who graciously guides and directs the intellect and the will of man lest these fall into error. Let, then, that continue to remain in a holy and inviolable union which neither can nor should be separated; and in all things-for this is the dictate of right reason itself-let God be dutifully and obediently served.