I answer that, As may be gathered from what has been said (Articles [2],3), with regard to the question in point, two things may be observed in connection with a judge. One is that he has to judge between accuser and defendant, while the other is that he pronounces the judicial sentence, in virtue of his power, not as a private individual but as a public person. Accordingly on two counts a judge is hindered from loosing a guilty person from his punishment. First on the part of the accuser, whose right it sometimes is that the guilty party should be punished---for instance on account of some injury committed against the accuser---because it is not in the power of a judge to remit such punishment, since every judge is bound to give each man his right. Secondly, he finds a hindrance on the part of the commonwealth, whose power he exercises, and to whose good it belongs that evil-doers should be punished.
Nevertheless in this respect there is a difference between judges of lower degree and the supreme judge, i.e. the sovereign, to whom the entire public authority is entrusted. For the inferior judge has no power to exempt a guilty man from punishment against the laws imposed on him by his superior. Wherefore Augustine in commenting on John 19:11, "Thou shouldst not have any power against Me," says (Tract. cxvi in Joan.): "The power which God gave Pilate was such that he was under the power of Caesar, so that he was by no means free to acquit the person accused." On the other hand the sovereign who has full authority in the commonwealth, can lawfully remit the punishment to a guilty person, provided the injured party consent to the remission, and that this do not seem detrimental to the public good.