Deuteronomy 17:5-7

American Standard Version

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. ⁷ The hand of the witnesses shall be first upon him to put him to death, and afterward the hand of all the people. So thou shalt put away the evil from the midst of thee.