Deuteronomy 17:4-6

New Catholic Bible

⁴ and you are told about it, and you hear of it, then you shall carefully check into it. If it is true, then an abomination has been committed in Israel; ⁵ you are to bring that man or woman who has done this evil thing to the town gates, and you shall stone that man or woman to death.

⁶ A person can be put to death upon the testimony of two or three witnesses; a person is not to be put to death upon the testimony of a single witness.