At dawn he appeared again in the temple courts, where all the people gathered around him, and he sat down to teach them. The teachers of the law and the Pharisees brought in a woman caught in adultery. They made her stand before the group and said to Jesus, “Teacher, this woman was caught in the act of adultery. In the Law Moses commanded us to stone such women. Now what do you say?” They were using this question as a trap, in order to have a basis for accusing him.
But Jesus bent down and started to write on the ground with his finger. When they kept on questioning him, he straightened up and said to them, “Let any one of you who is without sin be the first to throw a stone at her.” Again he stooped down and wrote on the ground.
At this, those who heard began to go away one at a time, the older ones first, until only Jesus was left, with the woman still standing there. Jesus straightened up and asked her, “Woman, where are they? Has no one condemned you?”
“No one, sir,” she said.
“Then neither do I condemn you,” [Jesus declared.] “Go now and leave your life of sin.” (John 8:1-11)
“The kingdom of Christ is not one of condemnation,” [Jesus tells the woman.] “I am not here to condemn you, but to remit the sins of those who, like you, are where death, the devil, evil consciences, accusers, and judges have come to plague them.”
“The slogan in My kingdom is: I forgive you your sin; for in my kingdom no one is without forgiveness of sins. Therefore, you, too, must have forgiveness.”
These Pharisees [who brought the woman to Jesus] did not have to become sinners; they were sinners already. And they became even greater sinners when Christ uncovered their sins. [He said,] “Let him who is without sin among you be the first to throw a stone at her.” …
Now they became sinners. But they despaired and slunk away. In their arrogance they hid their sin and would not await Christ’s second statement: “Neither do I condemn you.”
Thus, only those sinners belong in the kingdom of Christ who recognize their sin, feel it, and then catch hold of the Word of Christ spoken here: “I do not condemn you.” These people constitute the membership of Christ’s kingdom….
If sinners enter, they do not remain sinners. He spreads his cloak over their sins and says: “If you have sinned, I remit your sins and cover them.”
To be sure, sin is there. But the Lord in this kingdom closes his eyes to it, covers it, forgives it, and does not impute it to the sinner. So a living saint and member of Christ stands here, made out of an adulteress who had been infested with sin but whose sin is now forgiven and covered….
If you have tasted the law and sin, and if you know the ache of sin, then look here, and see how sweet, in comparison, the grace of God is, the grace which is offered to us in the gospel. This is the absolution which the adulteress receives here from the Lord Christ.
Source: Martin Luther, Luther’s Works, Volume 23; John 8:10-11.