In John 8 we read a story about a time the Jewish scribes and Pharisees tested Jesus. They brought him a woman whom they claimed was “taken in adultery, in the very act.” Their wording was very precise because they were attempting to state a legal charge. They even mentioned that the law said such a person was to be stoned. Jesus seemed to ignore them until they persisted in their question. At that point Jesus delivered the line, “Let him that is without sin cast the first stone.” Thereupon all the accusers left, and Jesus sent the woman away.
Many people have pointed out the obvious flaw in this story. If the woman was taken in the very act of adultery there must have been a man also taken. He also would be subject to stoning. It seems that Jesus could have used this as a way to respond. But he didn’t. Or at least it appears that he did not. Some people do suggest that what Jesus meant by his statement was “let him who is without this sin cast the first stone." That, if it were true, could mean that he was either directing that any man in the group who had never committed adultery initiate the punishment, or that he knew the man who had been caught with her was present and he was asking him to admit his own guilt by casting the first stone. Either of those interpretations, however, ask that we insert a word into the scripture that most authorities say is not there.
If that “this” is not there, then what was Jesus saying and why did the men leave? On the face of it, he is simply stating that if any of the men were totally sinless they could initiate the punishment. The problem with that interpretation is that such a requirement would negate the whole Law of Moses. If he is saying that the only person who could “throw the switch” was one who was totally sinless, then he is also saying that any stoning in the past were invalid, even the one in Leviticus 24 that was specifically commanded by God.
If he is not saying that only those who had never sinned were allowed to cast the first stone, then what is Jesus saying? One possibility is that he is reminding them that if they are going to ask him a question about the Law, they should be very careful that they are bringing charges according to the law. In reminding them of the law he was reminding them that conviction required at least two witnesses. Included in this would be the implicit accusation that they were showing partiality by only accusing the woman, but it goes beyond that.
In Deuteronomy 13:6-11 one of the provisions of the law for stoning a person who tries to draw one away to worship other gods is that the person who heard the accused was to be the first to cast the stones. Presumably that condition would apply in all cases of stoning. If so, then Jesus is simply asking who the primary witnesses are. Those who caught the couple in their sin should step forward and take the responsibility of initiating the punishment.
If this is an accurate interpretation of the incident, then what of the phrase “him that is without sin?” One of the Ten Commandments prohibited falsely witnessing against another. In that context, Jesus may be telling the men that he will answer their question if he can find two men willing to cast the first stone; that is, who are willing to admit that they truly caught the woman in the very act of sin. If nobody was willing to certify that they were true witnesses (without the sin of bringing a false accusation), then the question of whether to stone the woman or not was moot; they were caught trying to test him with a false case.