Objection 1: It would seem that custom cannot obtain force of law, nor abolish a law. Because human law is derived from the natural law and from the Divine law, as stated above (Q[93], A[3]; Q[95], A[2]). But human custom cannot change either the law of nature or the Divine law. Therefore neither can it change human law.
Objection 2: Further, many evils cannot make one good. But he who first acted against the law, did evil. Therefore by multiplying such acts, nothing good is the result. Now a law is something good; since it is a rule of human acts. Therefore law is not abolished by custom, so that the mere custom should obtain force of law.
Objection 3: Further, the framing of laws belongs to those public men whose business it is to govern the community; wherefore private individuals cannot make laws. But custom grows by the acts of private individuals. Therefore custom cannot obtain force of law, so as to abolish the law.
On the contrary, Augustine says (Ep. ad Casulan. xxxvi): "The customs of God's people and the institutions of our ancestors are to be considered as laws. And those who throw contempt on the customs of the Church ought to be punished as those who disobey the law of God."
I answer that, All law proceeds from the reason and will of the lawgiver; the Divine and natural laws from the reasonable will of God; the human law from the will of man, regulated by reason. Now just as human reason and will, in practical matters, may be made manifest by speech, so may they be made known by deeds: since seemingly a man chooses as good that which he carries into execution. But it is evident that by human speech, law can be both changed and expounded, in so far as it manifests the interior movement and thought of human reason. Wherefore by actions also, especially if they be repeated, so as to make a custom, law can be changed and expounded; and also something can be established which obtains force of law, in so far as by repeated external actions, the inward movement of the will, and concepts of reason are most effectually declared; for when a thing is done again and again, it seems to proceed from a deliberate judgment of reason. Accordingly, custom has the force of a law, abolishes law, and is the interpreter of law.
Reply to Objection 1: The natural and Divine laws proceed from the Divine will, as stated above. Wherefore they cannot be changed by a custom proceeding from the will of man, but only by Divine authority. Hence it is that no custom can prevail over the Divine or natural laws: for Isidore says (Synon. ii, 16): "Let custom yield to authority: evil customs should be eradicated by law and reason."
Reply to Objection 2: As stated above (Q[96], A[6]), human laws fail in some cases: wherefore it is possible sometimes to act beside the law; namely, in a case where the law fails; yet the act will not be evil. And when such cases are multiplied, by reason of some change in man, then custom shows that the law is no longer useful: just as it might be declared by the verbal promulgation of a law to the contrary. If, however, the same reason remains, for which the law was useful hitherto, then it is not the custom that prevails against the law, but the law that overcomes the custom: unless perhaps the sole reason for the law seeming useless, be that it is not "possible according to the custom of the country" [*Q[95], A[3]], which has been stated to be one of the conditions of law. For it is not easy to set aside the custom of a whole people.
Reply to Objection 3: The people among whom a custom is introduced may be of two conditions. For if they are free, and able to make their own laws, the consent of the whole people expressed by a custom counts far more in favor of a particular observance, that does the authority of the sovereign, who has not the power to frame laws, except as representing the people. Wherefore although each individual cannot make laws, yet the whole people can. If however the people have not the free power to make their own laws, or to abolish a law made by a higher authority; nevertheless with such a people a prevailing custom obtains force of law, in so far as it is tolerated by those to whom it belongs to make laws for that people: because by the very fact that they tolerate it they seem to approve of that which is introduced by custom.
Whether the rulers of the people can dispense from human laws?
Objection 1: It would seem that the rulers of the people cannot dispense from human laws. For the law is established for the "common weal," as Isidore says (Etym. v, 21). But the common good should not be set aside for the private convenience of an individual: because, as the Philosopher says (Ethic. i, 2), "the good of the nation is more godlike than the good of one man." Therefore it seems that a man should not be dispensed from acting in compliance with the general law.
Objection 2: Further, those who are placed over others are commanded as follows ( Dt. 1:17 ): "You shall hear the little as well as the great; neither shall you respect any man's person, because it is the judgment of God." But to allow one man to do that which is equally forbidden to all, seems to be respect of persons. Therefore the rulers of a community cannot grant such dispensations, since this is against a precept of the Divine law.
Objection 3: Further, human law, in order to be just, should accord with the natural and Divine laws: else it would not "foster religion," nor be "helpful to discipline," which is requisite to the nature of law, as laid down by Isidore (Etym. v, 3). But no man can dispense from the Divine and natural laws. Neither, therefore, can he dispense from the human law.
On the contrary, The Apostle says ( 1 Cor. 9:17 ): "A dispensation is committed to me."
I answer that, Dispensation, properly speaking, denotes a measuring out to individuals of some common goods: thus the head of a household is called a dispenser, because to each member of the household he distributes work and necessaries of life in due weight and measure. Accordingly in every community a man is said to dispense, from the very fact that he directs how some general precept is to be fulfilled by each individual. Now it happens at times that a precept, which is conducive to the common weal as a general rule, is not good for a particular individual, or in some particular case, either because it would hinder some greater good, or because it would be the occasion of some evil, as explained above (Q[96], A[6]). But it would be dangerous to leave this to the discretion of each individual, except perhaps by reason of an evident and sudden emergency, as stated above (Q[96], A[6]). Consequently he who is placed over a community is empowered to dispense in a human law that rests upon his authority, so that, when the law fails in its application to persons or circumstances, he may allow the precept of the law not to be observed. If however he grant this permission without any such reason, and of his mere will, he will be an unfaithful or an imprudent dispenser: unfaithful, if he has not the common good in view; imprudent, if he ignores the reasons for granting dispensations. Hence Our Lord says ( Lk. 12:42 ): "Who, thinkest thou, is the faithful and wise dispenser [Douay: steward], whom his lord setteth over his family?"
Reply to Objection 1: When a person is dispensed from observing the general law, this should not be done to the prejudice of, but with the intention of benefiting, the common good.
Reply to Objection 2: It is not respect of persons if unequal measures are served out to those who are themselves unequal. Wherefore when the condition of any person requires that he should reasonably receive special treatment, it is not respect of persons if he be the object of special favor.
Reply to Objection 3: Natural law, so far as it contains general precepts, which never fail, does not allow of dispensations. In other precepts, however, which are as conclusions of the general precepts, man sometimes grants a dispensation: for instance, that a loan should not be paid back to the betrayer of his country, or something similar. But to the Divine law each man stands as a private person to the public law to which he is subject. Wherefore just as none can dispense from public human law, except the man from whom the law derives its authority, or his delegate; so, in the precepts of the Divine law, which are from God, none can dispense but God, or the man to whom He may give special power for that purpose.