Libertas §7

⁷ Such, then, being the condition of human liberty, it necessarily stands in need of light and strength to direct its actions to good and to restrain them from evil. Without this, the freedom of our will would be our ruin. First of all, there must be law ; that is, a fixed rule of teaching what is to be done and what is to be left undone. This rule cannot affect the lower animals in any true sense, since they act of necessity, following their natural instinct, and cannot of themselves act in any other way. On the other hand, as was said above, he who is free can either act or not act, can do this or do that, as he pleases, because his judgment precedes his choice. And his judgment not only decides what is right or wrong of its own nature, but also what is practically good and therefore to be chosen, and what is practically evil and therefore to be avoided. In other words, the reason prescribes to the will what it should seek after or shun, in order to the eventual attainment of man's last end, for the sake of which all his actions ought to be performed. This ordination of reason is called law. In man's free will, therefore, or in the moral necessity of our voluntary acts being in accordance with reason, lies the very root of the necessity of law. Nothing more foolish can be uttered or conceived than the notion that, because man is free by nature, he is therefore exempt from law. Were this the case, it would follow that to become free we must be deprived of reason; whereas the truth is that we are bound to submit to law precisely because we are free by our very nature. For, law is the guide of man's actions; it turns him toward good by its rewards, and deters him from evil by its punishments.