Ireneus...
Jesus upheld the law perfectly. It was His stated mission to do the will of His Father. He in know way tried to say or show that the law meant nothing or undermine Moses. He even told assembled crowds to OBEY what the Pharisees say when they are sitting in the seat of Moses (teaching the law without adding to it or taking away from it) matthew 23:3
When the Pharisees brought the women caught in adultery to Jesus and said the law commanded that she be stoned, that isn't the law of God. It may have become a tradition in the oral or extra-biblical "law" of the Pharisees, but not the law of God.
The law of God stated that both the man and the woman are to be brought before the judge together, there must be 2 or 3 witnesses to the act of adultery and if found guilty, the very people who charged them with adultery were the ones who were supposed to stone both the man and woman. The Pharisees were violating the law. That's why Jesus said, "he who is without sin, cast the first stone."