Deuteronomy 19:15

15 One witness shall not stand to testify against a man for any iniquity, or for any fault, or for any sin which he may commit; by the mouth of two witnesses, or by the mouth of three witnesses, shall every word be established.

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 Thine eye shall not spare him; so shalt thou purge innocent blood from Israel, and it shall be well with thee.
14 Thou shalt not move the landmarks of thy neighbour, which thy fathers set in the inheritance, in which thou hast obtained a share in the land, which the Lord thy God gives thee to inherit.
15 One witness shall not stand to testify against a man for any iniquity, or for any fault, or for any sin which he may commit; by the mouth of two witnesses, or by the mouth of three witnesses, shall every word be established.
16 And if an unjust witness rise up against a man, alleging iniquity against him;
17 then shall the two men between whom the controversy is, stand before the Lord, and before the priests, and before the judges, who may be in those days.

Footnotes 1

The Brenton translation of the Septuagint is in the public domain.