They went each to his own house, but Jesus went to the Mount of Olives. Early in the morning he came again to the temple. All the people came to him, and he sat down and taught them. The scribes and the Pharisees brought a woman who had been caught in adultery, and placing her in the midst they said to him, “Teacher, this woman has been caught in the act of adultery. Now in the Law Moses commanded us to stone such women. So what do you say?” This they said to test him, that they might have some charge to bring against him. Jesus bent down and wrote with his finger on the ground. And as they continued to ask him, he stood up and said to them, “Let him who is without sin among you be the first to throw a stone at her.” And once more he bent down and wrote on the ground. But when they heard it, they went away one by one, beginning with the older ones, and Jesus was left alone with the woman standing before him. Jesus stood up and said to her, “Woman, where are they? Has no one condemned you?” She said, “No one, Lord.” And Jesus said, “Neither do I condemn you; go, and from now on sin no more.”John 7:53 - 8:11
This "let he who is without sin, cast the first stone" incident is one of the most well-known lessons of the Bible. A woman, who had been caught in the act of adultery was brought to Jesus Christ by the scribes and Pharisees as a test to see if the Messiah was a liberal in matters of the Law of God. In response to their deceitful query, He didn't condemn the woman, not because He was a liberal, not because He condoned her sin, but because the men who brought the woman to Him were hypocrites. He was the only person there that day who was free of sin, the only one who had the right to "cast the first stone." He didn't stone her (or her accusers), but instead forgave her and told her to "sin no more." Otherwise, the day is coming when she, if she didn't thereafter repent, wouldn't be stoned, but be burned - along with the hypocrites who brought her to Him that day, if they didn't thereafter repent of their sin:
Blessed are those who wash their robes, so that they may have the right to the tree of life and that they may enter the city by the gates. Outside are the dogs and sorcerers and the sexually immoral and murderers and idolaters, and everyone who loves and practices falsehood. (Revelation 22:14-15)
It seems, perhaps, that Jesus Christ wasn't the only one who was "set up" that day. While they used the woman caught in adultery as the means to try to entrap Him through His answer, the woman herself may have been partly entrapped - the man that she was "taken in adultery, in the very act" with (by definition, if she was "caught in the act," the man had to have been caught too) was not brought to Him with her. Whoever he was, he was just as guilty and just as subject to "If a man commits adultery with the wife of his neighbor, both the adulterer and the adulteress shall surely be put to death." (Leviticus 20:10) that the scribes and Pharisees quoted in condemning the woman. Letting him go was more hypocrisy on the part of the themselves-adulterous scribes and Pharisees.
The Pericope Adulterae is a traditional name for the famous passage (pericope) quoted above about Jesus and the woman taken in adultery from verses 7:53-8:11 of the Gospel of John. The parable, and its messages of suspension of judgment when one is not blameless and tempering justice with mercy, have endured in Christian thought. Both "let him who is without sin, cast the first stone" and "go, and sin no more" have found their way into common usage. The English idiomatic phrase to "cast the first stone" is derived from this passage.
Today, we have our own scribes and Pharisees who want to condemn the LGBT community, yet they do not head the words of Jesus. Some of the loudest of those who condemn us are those who have sinned the most. Hypocrites are the reason why so many turn away from religion. They say one thing and do another, and religion is full of hypocrites. Does that mean we should discredit the teachings of Jesus? Absolutely not. It merely means that we should be vigilant with the Truth of God's Word. God is the only one who can judge us, but we all judge others. I'm not without sin either, and I have certainly judged people before and is one of my great flaws (of which I have many).
Instead of casting stones, we should climb above our own stones in order to be better people. God loves us no matter what we do, that love is eternal. The hate and judgmental behavior are the work of the devil. As long as we are divided and are not following God's word, then Satan is winning the battle. None of us are perfect, yet we must strive to be better each day.