Exodus 20:14
You shall not commit adultery

Deuteronomy 5:18
You shall not commit adultery.

Leviticus 20:10
The man who commits adultery with another man’s wife, he who commits adultery with his neighbor’s wife, the adulterer and the adulteress, shall surely be put to death.

John 8:3–11
Then the scribes and Pharisees brought to Him a woman caught in adultery. And when they had set her in the midst, they said to Him, “Teacher, this woman was caught in adultery, in the very act. Now Moses, in the law, commanded us that such should be stoned. But what do You say?”

This they said, testing Him, that they might have something of which to accuse Him. But Jesus stooped down and wrote on the ground with His finger, as though He did not hear. So when they continued asking Him, He raised Himself up and said to them, “He who is without sin among you, let him throw a stone at her first.” And again He stooped down and wrote on the ground.

Then those who heard it, being convicted by their conscience, went out one by one, beginning with the oldest even to the last. And Jesus was left alone, and the woman standing in the midst. When Jesus had raised Himself up and saw no one but the woman, He said to her, “Woman, where are those accusers of yours? Has no one condemned you?”

She said, “No one, Lord.” And Jesus said to her, “Neither do I condemn you; go and sin no more.”

Deuteronomy 17:6
Whoever is deserving of death shall be put to death on the testimony of two or three witnesses; he shall not be put to death on the testimony of one witness.

Deuteronomy 19:15
One witness shall not rise against a man concerning any iniquity or any sin that he commits; by the mouth of two or three witnesses the matter shall be established.

In the passage referred to, a woman is brought to Jesus by the religious leaders who were interested in trapping Him in a difficult situation. Many apparent witnesses have been found to condemn this woman who has been caught in the very act of adultery. According to the laws given to Moses and laid out in Exodus, Leviticus, and Deuteronomy, adultery was a sin punishable by death—for the man and the woman! It is interesting to note that only the woman was brought before Jesus. This exposes the motives of the religious leaders. They were not interested in justice, but in accusing Jesus so they might discredit His authority.

One of the requirements of the administration of justice laid out in the Mosaic Law was that there must be agreement between two or three witnesses (Deuteronomy 17:6, 19:15) to condemn the accused. Jesus also faced this same standard in the trial that was held before Caiaphas (Matthew 26:57–60). When the witnesses were not in agreement, they were dismissed until two that were in agreement could be found.

After the leaders present the accused woman to Jesus, He stoops and writes something on the ground, ignoring the leaders. Though Scripture does not record what He wrote, some have speculated it was the Ten Commandments. Regardless, the leaders were convicted of their own sinfulness when Jesus asked them to cast the first stone. As they walk away one by one, the woman is left standing alone. With no witnesses to accuse her, Jesus is justified in letting her go. He is not violating the Mosaic Law referenced by the Jewish leaders as there are no witnesses to provide testimony to condemn her.

Jesus exercises grace in His treatment of the woman without violating the letter of the Law. As God in the flesh, Jesus also has the authority to forgive sins (Matthew 9:6). It is clear from the text and a proper understanding of the application of Mosaic Law that the contradiction is apparent, and not real.