Thomas Aquinas

“ He who lies in court by denying his guilt, acts both against the love of God to whom judgment belongs, and against the love of his neighbor, and this not only as regards the judge, to whom he refuses his due, but also as regards his accuser, who is punished if he fail to prove his accusation. Hence it is written (Ps. 140:4) : "Incline not my heart to evil words, to make excuses in sins": on which words a gloss says: "Shameless men are wont by lying to deny their guilt when they have been found out." ”

“ To lie, with injury to another person, in order to rescue a man from death is not a purely officious lie, for it has an admixture of the pernicious lie: and when a man lies in court in order to exculpate himself, he does an injury to one whom he is bound to obey, since he refuses him his due, namely an avowal of the truth. ”

“ That a man is sometimes unwilling to commit a sin in order to escape from the death of the body, the danger of which threatens the accused who is on trial for his life, is an act of perfect virtue, since "death is the most fearful of all temporal things" (Ethic. iii, 6) . Wherefore if the accused, who is on trial for his life, bribes his adversary, he sins indeed by inducing him to do what is unlawful, yet the civil law does not punish this sin, and in this sense it is said to be lawful. ”

“ I answer that, A man may be condemned to death in two ways. First justly, and then it is not lawful for the condemned to defend himself, because it is lawful for the judge to combat his resistance by force, so that on his part the fight is unjust, and consequently without any doubt he sins. ”

“ If the accuser is guilty of collusion with the accused and the latter is guilty, he incurs punishment, and so it is evident that he sins. Wherefore, since it is a sin to induce a man to sin, or to take part in a sin in any way---for the Apostle says (Rom. 1:32) , that "they . . . are worthy of death . . . that consent" to those who sin---it is evident that the accused also sins if he is guilty of collusion with his adversary. Nevertheless according to human laws no punishment is inflicted on him, for the reason given above. ”

“ Moreover it would seem to point to levity of mind for a man not to abide by what he has once approved of. Hence it is with reason that the law refuses us the faculty of appealing from the decision of judges of our own choice, who have no power save by virtue of the consent of the litigants. On the other hand the authority of an ordinary judge depends, not on the consent of those who are subject to his judgment, but on the authority of the king or prince who appointed him. ”

“ But it is unlawful for him, either to utter a falsehood, or to withhold a truth that he is bound to avow, or to employ guile or fraud, because fraud and guile have the force of a lie, and so to use them would be to defend oneself with calumnies.
'Reply to Objection 1:' Human laws leave many things unpunished, which according to the Divine judgment are sins, as, for example, simple fornication; because human law does not exact perfect virtue from man, for such virtue belongs to few and cannot be found in so great a number of people as human law has to direct. ”

“ As regards what he may do lawfully, a man can employ either lawful means, and such as are adapted to the end in view, which belongs to prudence; or he can use unlawful means, unsuitable to the proposed end, and this belongs to craftiness, which is exercised by fraud and guile, as shown above (Q [55] , AA [3] , seqq.) ”

“ Further, it is written (Prov. 24:11) : "Deliver them that are led to death: and those that are drawn to death forbear not to deliver." Now a man is under greater obligation to himself than to another. Therefore it is lawful for a condemned man to defend himself from being put to death. ”

“ Now when a judge oppresses anyone unjustly, in this respect he departs from the order of the higher authority, whereby he is obliged to judge justly. Hence it is lawful for a man who is oppressed unjustly, to have recourse to the authority of the higher power, by appealing either before or after sentence has been pronounced. And since it is to be presumed that there is no rectitude where true faith is lacking, it is unlawful for a Catholic to appeal to an unbelieving judge, according to Decretals II, qu. ”

“ Secondly a man is condemned unjustly: and such a sentence is like the violence of robbers, according to Ezech. 22:21, "Her princes in the midst of her are like wolves ravening the prey to shed blood." Wherefore even as it is lawful to resist robbers, so is it lawful, in a like case, to resist wicked princes ”