Catholic Encyclopedia (1913)/Stoning in Scripture
Palestine being a very rocky country, the abundance of stones made it natural to use them as missiles. Stone throwing might be merely a mark of hatred and contempt (II Kings 16:6-13), or the means of carrying out murderous intentions against which provision had to be made in the Law (Exodus 21:18, Numbers 35:17). Stoning to death which was at first an expression of popular fury analogous to "lynching", later came to be a natural and legally recognized method of execution. It was this regulated by law as an appointed means of capital punishment (Deuteronomy 17:5-7; Acts 7:58). Death by stoning is prescribed in the Pentateuch as the penalty for eighteen different crimes including Sabbath-breaking, but for one crime only — murder — is it the penalty prescribed in all the codes. The execution of the criminal usually took place outside the city walls, and according to Deuteronomy 16:7, the witnesses in the case were to cast the first stone: "Thou shalt bring forth the man or the woman, who have committed that most wicked thing, to the gates of thy city, and they shall be stoned. By the mouth of two or three witnesses shall he die who is to be slain.... The hands of the witnesses shall be first upon him to kill him, and afterwards the hands of the rest of the people". (Deuteronomy 17:5-7). Stoning is also mentioned in Acts 7:57-58, as the means by which Stephen the first Christian martyr was put to death: "And casting him forth without the city, they stoned him."
James F. Driscoll.