Deuteronomy 19:15

15 "One witness alone will not be sufficient to convict a person of any offense or sin of any kind; the matter will be established only if there are two or three witnesses testifying against him.

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 You are not to pity him. Rather, you must put an end to the shedding of innocent blood in Isra'el. Then things will go well with you.

14 "You are not to move your neighbor's boundary marker from the place where people put it long ago, in the inheritance soon to be yours in the land ADONAI your God is giving you to possess.

15 "One witness alone will not be sufficient to convict a person of any offense or sin of any kind; the matter will be established only if there are two or three witnesses testifying against him.

16 "If a malicious witness comes forward and gives false testimony against someone,

17 then both the men involved in the controversy are to stand before ADONAI, before the cohanim and the judges in office at the time.