Deuteronomy 19:16

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.