Calvin's Commentaries, Vol. 5: Harmony of the Law, Part III, tr. by John King, [1847-50], at sacred-texts.com
Supplement to the Ninth Commandment
16. If a false witness rise up against any man, to testify against him that which is wrong;
16. Quum steterit testis mendax contra aliquem, ut testificetur contra eum verbum perversum:
17. Then both the men, between whom the controversy is, shall stand before the Lord, before the priests and the judges which shall be in those days:
17. Tunc stabunt duo illi homines quibus est lis, coram Jehova, id est coram sacerdotibus et judicibus qui fuerint in diebus illis.
18. And the judges shall make diligent inquisition: and, behold, if the witness be a false witness, and hath testified falsely against his brother;
18. Et inquirent judices diligenter, et si testis ille est testis mendax, mendacium testificatus est contra fratrem suum:
19. Then shall ye do unto him as he had thought to have done unto his brother: so shalt thou put the evil away from among you.
19. Facietis ei, quemadmodum cogitavit facere fratri suo, et auferes malum e medio tui.
20. And those which remain shall hear, and fear, and shall henceforth commit no more any such evil among you.
20. Et qui remanserint, audient ac timebunt, nec addent facere ultra malum simile huic in medio tui.
21. And thine eye shall not pity; but life shall go for life, eye for eye, tooth for tooth, hand for hand, foot for foot.
21. Neque parcet oculus tuus: animam pro anima, oculum pro oculo, dentem pro dente, manum pro manu, pedem pro pede.
16. If a false witness rise up against any man. Because the fear of God does not so prevail in all men, as that they should voluntarily abstain from the love of slander, God here appoints the punishment to be inflicted for perjury: for political laws are enacted against the ungodly and disobedient, in order that those who despise God’s judgment should be brought before the tribunal of men. Although perjury is not here ordained to be tried before the judges, unless there should be an accuser, who should complain that he had been unjustly injured by false-witness, still reason dictates, that if any man have been condemned to death by false-witnesses, the judges should not hesitate to make an official inquiry into the matter. Yet, inasmuch as men are generally disposed to assert their own innocence, God has deemed it sufficient to put the case, that if any complaint should be lodged, the judges should diligently investigate it, and if the crime be proved, should inflict the punishment of retaliation (talionis.) Whence it appears that false-witnesses and murderers stand in the same light before God. By commanding that the inquiry should be made not only by the judges, but also by the priests, as if God Himself were present, He shews that He requires unusual diligence to be used; because a secret crime is not easily detected without the most anxious care.