Deuteronomy 17:4-6 Common English Bible (CEB)
4 and you hear news about it, then you must look into this situation very carefully. And if it’s definitely true that this detestable thing was done in Israel, 5 then you must bring out the man or woman who has done this evil thing to the gates of the city. Stone that person until he or she is dead.
6 Capital punishment must be decided by two or three witnesses. No one may be executed on the basis of only one testimony.