The entire code of Mosaic law was just. Indeed, as a code of law directly from God, it is perhaps the most just code of laws ever written. Yet Jesus was clear (such as when he saved the woman from being stoned) that even so it should not always be carried out to the full extent that it could be.
Really? Jesus said that not even a punctuation mark will pass away from the Law until heaven and earth shall pass away.
Jesus' only disagreement was with certain INTERPRETATIONS of Torah. The Pharisees were divided into two schools:
- Bet Hillel: this school was more into the spirit of the law, was the more lenient of the two. This was the school that taught, i.e., that it was lawful for a person to heal via prayer on the Sabbath. This was the school of thought that Jesus followed and supported. I think we can supposed that Pharisees such as Nicodemus who followed Jesus were also of this school
- Bet Shammai: This school was highly legalistic and strict. In every case where the Pharisees argue with Jesus in the gospels, the position represented by the Pharisees is the Bet Shammai position. This is because during the years of Jesus' ministry, the school of Shammai was in power in the Sanhedron.
If you read the Talmud, you will find LOTS of arguments between Rabbis, and certainly arguments between Hillel and Shammai, and their followers. This is because debate is the way that Jews learn. Such arguments are an integral part of Jewish culture. Jesus' arguments with the bet Shammai Pharisees should be seen in that light.
What is MORE TELLING is that you don't hear Jesus arguing with bet Hillel Pharisees.
In many cases, Christians who are unfamiliar with Jewish law simply don't understand what is going on in the gospels. For example, the woman caught in adultery is being chased by what is essentially a lynch mob. A mob does not have the Godly authority to convict and execute ANYONE. She had not gone before a beit din (Jewish court of Law), or she wouldn't have been being chased. A beit din would have rightly convicted and sentenced her, and Jesus would not have protested, since God himself gave them the authority to do so.
You ARE CORRECT however, that the proscribed penalties of the Torah are the maximum penalties, not the mandatory penalties.
For example, let's say a woman was abandoned by her husband, and is unable to afford to feed herself and her three children on what she can make by herself. Along comes Shmuel bar Abraham who falls for her. They can't marry since she can't get a divorce. So it's a secret relationship. Eventually it is found out and taken before the beit din. The rabbis understand that it is adultery, but they will also weigh in the fact that she has been abandoned, etc. etc. and will not have her executed.
And indeed, throughout Jewish history, if a beit din executes more than one person in 70 years, it is considered a bloody court.