Deuteronomy 19:15

“One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth, etc.] Whether capital sins, or pecuniary debts; or whatsoever sins a man may be guilty of whether sins against the first or second table of the law, whether greater or lesser sins, whether in moral or civil things; the Jews except only in the case of a woman suspected of adultery and of beheading the heifer: at the mouth of two witnesses, or at the mouth of three witnesses, shall the matter be established; either for acquittance or condemnation; and the witnesses may not, as Jarchi says, write their testimony in a letter, and send it to the sanhedrim, nor may an interpreter stand between…”

“TWO WITNESSES REQUIRED. (Deu 19:15) One witness shall not rise up against a man for any iniquity--The following rules to regulate the admission of testimony in public courts are founded on the principles of natural justice. A single witness shall not be admitted to the condemnation of an accused person.”

“Rise - Or be established, accepted, owned as sufficient: it is the same word which in the end of the verse is rendered, be established. Deuteronomy 19:16”

“19:15 The word of one witness alone would count no more than the word of the accused. However, two or three witnesses would confirm or discount each other’s testimony. For New Testament references to this law, see Matt 18:15-20; John 8:17-18; 2 Cor 13:1-2 and study note.”

“at the mouth: Deu 17:6; Num 35:30; Kg1 21:10, Kg1 21:13; Mat 18:16, Mat 26:60, Mat 26:61; Joh 8:17; Co2 13:1; Ti1 5:19; Heb 10:28; Rev 11:3-7 Deuteronomy 19:16”

“The Punishment of a False Witness. - To secure life and property against false accusations, Moses lays down the law in Deu 19:15, that one witness only was not "to rise up against any one with reference to any crime or sin, with every sin that one commits" (i.e., to appear before a court of justice, or be accepted as sufficient), but everything was to be established upon the testimony of two or three witnesses. The rule laid down in Deu 17:6 and Num 35:30 for capital crimes, is raised hereby into a law of general application (see at Num 35:30). קוּם (in Deu 19:15), to stand, i.e., to acquire legal force. - But as it was not always possible to bring forward two or three witnesses, and the…”