Deuteronomy 17:6
King James Version
“At the mouth of two witnesses, or three witnesses, shall he that is worthy of death be put to death; at the mouth of one witness he shall not be put to death.”
Context
3And hath gone and served other gods, and worshipped them, either the sun, or moon, or any of the host of heaven, which I have not commanded;
4And it be told thee, and thou hast heard and enquired diligently, and, behold, true, the thing certain, such abomination is wrought in Israel:
5Then shalt thou bring forth that man or that woman, which have committed that wicked thing, unto thy gates, that man or that woman, and shalt stone them with stones, till they die.
6At the mouth of two witnesses, or three witnesses, shall he that is worthy of death be put to death; at the mouth of one witness he shall not be put to death.
7The hands of the witnesses shall be first upon him to put him to death, and afterward the hands of all the people. So thou shalt put the evil away from among you.
8If there arise a matter too hard for thee in judgment, between blood and blood, between plea and plea, and between stroke and stroke, matters of controversy within thy gates: then shalt thou arise, and get thee up into the place which the LORD thy God shall choose;
9And thou shalt come unto the priests the Levites, and unto the judge that shall be in those days, and enquire; and they shall shew thee the sentence of judgment: