Deuteronomy 17:5-7

5you must bring out to your gates the man or woman who has done this evil thing, and you must stone that person to death. 6On the testimony of two or three witnesses a man shall be put to death, but he shall not be executed on the testimony of a lone witness. 7The hands of the witnesses shall be the first in putting him to death, and after that, the hands of all the people. So you must purge the evil from among you.1