Deuteronomy 17:4-6

American Standard Version

⁴ and it be told thee, and thou hast heard of it; then shalt thou inquire diligently; and, behold, if it be true, and the thing certain, that such abomination is wrought in Israel, ⁵ then shalt thou bring forth that man or that woman, who hath done this evil thing, unto thy gates, even the man or the woman; and thou shalt stone them to death with stones. ⁶ At the mouth of two witnesses, or three witnesses, shall he that is to die be put to death; at the mouth of one witness he shall not be put to death.