Deuteronomy 17:4-6

Young's Literal Translation

⁴ and it hath been declared to thee, and thou hast heard, and hast searched diligently, and lo, truth; the thing is established; this abomination hath been done in Israel --

⁵ `Then thou hast brought out that man, or that woman, who hath done this evil thing, unto thy gates -- the man or the woman -- and thou hast stoned them with stones, and they have died.

⁶ By the mouth of two witnesses or of three witnesses is he who is dead put to death; he is not put to death by the mouth of one witness;