In a contested case, one of the primary ways to clarify what happened is to find witnesses. This allows the court to reach a reliable verdict. Therefore, if a person saw something which could help clarify an incident, the Torah obligates one to testify; it is a sin if one does not do so. (Leviticus 5:1). The judges must thoroughly examine witnesses to ensure there are no contradictions in their testimonies, and they have not extrapolated incorrectly based on what they saw. The Torah strongly exhorts against false testimony. This admonition is so important that it is the ninth of the Ten Commandments. Additionally, the Torah decrees fitting punishment for false witnesses: “If a man appears against another to testify maliciously . . . You shall do to him as he schemed to do to his fellow” (Deuteronomy 19:16-19).
