Under the Law of Moses, at least two witnesses were necessary to convict someone of a crime or offense.
The Law of Moses required multiple witnesses to convict someone of a crime or offense. It could not be done solely upon the testimony of one person’s claims.
15 “One witness shall not rise against a man about any injustice or offense or sin concerning which he may be guilty; by the mouth of two or three witnesses the matter shall be established.Deuteronomy 19:15 OSB
This is a wise practice. Humans are such flawed creatures that, even if we have pure motives, our perception of what transpired is often poor.
I’m reminded of how often, while watching a sporting event, I will definitively conclude that something occurred and the officials “made a bad call,” obviously(!), because they ruled differently than I “saw it.” And then, we watch the replay, and I was wrong, sometimes badly wrong. Oof!
Try as we might, what we “see” often isn’t close to what really happened.
Besides this, if judgments could be handed out—especially those carrying the death penalty—based solely upon what one person said happened, this obviously provides motive to lie or bear false witness for perceived personal gain.
Furthermore, having multiple witness accounts of what transpired ensures that the individual(s) who brought the accusation or shared the unfavorable testimony regarding another’s malicious or otherwise harmful actions was properly protected from slander or undeserved ill treatment by attacking their testimony’s accuracy.
Thus, requiring multiple witnesses is a wise protection for all involved.