The Pharisees confront Him with the supposedly impossible: condemning an adulteress to be stoned and thus certainly ending up in jail for violating Roman law, or, by letting her go, allowing for claims that he is not the Son of God by not upholding the Jewish law. As the Guile Hero that he is, Jesus simply replies "Let him who is without sin among you be the first to throw a stone at her." To which, everyone simply walks away as the realization of his words sinks in. Especially as He is the only one who can throw the first stone. After they all go, He asks the woman whether anyone remains to condemn her. Reply? "No one, Lord". His answer to that is "Then neither do I condemn you. Go, and leave your life of sin." There's more Awesomeness by Analysis going on there than most people realize. The Torah required that in a case of adultery, both parties had to be brought to judgment together, so where was the man? Moreover, Jewish law at the time stipulated that in any death penalty case, the witnesses were disqualified if they didn't try to warn the perpetrators against carrying out their crime. Finally, the witnesses themselves had to throw the first stones. Jesus basically disqualified the witnesses in a perfectly legal manner and then, since he himself hadn't witnessed the crime and therefore wasn't qualified to cast the first stone himself, warned the woman against repeating it to fulfill the Torah. Not to mention, the Torah requires there to be at least two witnesses. Jesus may have counted as one (since he knows all), but since everyone else left, there wasn't a second witness (the woman not withstanding, since she was also the accused). By getting rid of all the witnesses, there was no legal way to condemn her, which is why Jesus didn't.

Another one of Jesus' most awesome responses to the Pharisees comes in Luke 20:1-8:

Now it happened on one of those days, as He taught the people in the temple and preached the Gospel, that the chief priests and the scribes, together with the elders, confronted Him and spoke to Him, saying, "Tell us, by what authority are You doing these things? Or who is he who gave You this authority?" But He answered and said to them, "I also will ask you one thing, and answer me: the baptism of Johnwas it from heaven or from men?" And they reasoned among themselves, saying, "If we say, 'From heaven,' He will say, 'Why then did you not believe him?' But if we say, 'From men,' all the people will stone us, for they are persuaded that John was a prophet." So they answered, "We don't know." And Jesus said to them, "Neither will I tell you by what authority I do these things."