Contradiction with Leviticus 20:10
This verse prescribes the death penalty for adultery, which contrasts with John 8:1 where mercy is highlighted.
Leviticus 20:10: And the man that committeth adultery with [another] man's wife, [even he] that committeth adultery with his neighbour's wife, the adulterer and the adulteress shall surely be put to death.
Contradiction with Exodus 20:14
The commandment against adultery stands in contrast to the context of forgiveness in John 8:1.
Exodus 20:14: Thou shalt not commit adultery.
Contradiction with Deuteronomy 22:22
Similar to Leviticus 20:10, this verse mandates death for adultery, contradicting the theme of forgiveness in John 8:1.
Deuteronomy 22:22: If a man be found lying with a woman married to an husband, then they shall both of them die, [both] the man that lay with the woman, and the woman: so shalt thou put away evil from Israel.
Contradiction with Matthew 5:27-28
Jesus warns against even lusting, highlighting a stricter standard than what's implied by forgiveness in John 8:1.
Matthew 5:27-28: Ye have heard that it was said by them of old time, Thou shalt not commit adultery: