Deuteronomy 19:15

15 “You must not convict anyone of a crime on the testimony of only one witness. The facts of the case must be established by the testimony of two or three witnesses.

Deuteronomy 19:15 Meaning and Commentary

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
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 the witnesses and the judges; (See Gill on Deuteronomy 17:6).

Deuteronomy 19:15 In-Context

13 Do not feel sorry for that murderer! Purge from Israel the guilt of murdering innocent people; then all will go well with you.

14 “When you arrive in the land the LORD your God is giving you as your special possession, you must never steal anyone’s land by moving the boundary markers your ancestors set up to mark their property.

15 “You must not convict anyone of a crime on the testimony of only one witness. The facts of the case must be established by the testimony of two or three witnesses.

16 “If a malicious witness comes forward and accuses someone of a crime,

17 then both the accuser and accused must appear before the LORD by coming to the priests and judges in office at that time.