As I said, Paul never said that anyone should ignore the Law of Moses. He just said that the Law was incapable of bringing salvation.
That's not entirely true. Look at what Saul said in his Philippian letter:
4 Though I might also have confidence in the flesh. If any other man thinketh that he hath whereof he might trust in the flesh,
I more:
5 Circumcised the eighth day, of the stock of Israel, of the tribe of Benjamin, an Hebrew of the Hebrews;
as touching the law, a Pharisee;
6 Concerning zeal, persecuting the church;
touching the righteousness which is in the law, blameless.
Philippians 3:4–6.
By claiming to be "blameless" where the Law is concerned, Saul is saying that he is 'justified.'
"As touching the Law, a Pharisee."
"[as] touching the righteousness
which is in the Law, blameless."
What an extraordinary thing to say. "Righteousness [which]
is in the Law, blameless?" According to Scripture anyone who is "justified" is saved. God has declared the person, "Not Guilty!" of transgressing the Law. This is salvation.
But Saul says the opposite in Galatians:
16 Knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law:
for by the works of the law shall no flesh be justified. Galatians 2:16.
Clearly, we see Saul's double mindedness. Which is it, Saul?
Saul was a rabbi and Pharisee. He, and Jesus, also a rabbi, both taught the people from out of the Law and the Prophets. He taught nothing else for the Law and the Prophets was his ministry. Soon after his conversion on the road to Damascus Saul disappeared for about 14-17 years, until Barnabas went and brought him to Antioch (Syria) where he pastored the sheep in that city. In Acts 13:1-4 we see Saul and Barnabas were in this church when the spirit of prophecy came upon one of the prophets there and the Holy Spirit - through prophecy - said to "separate Saul and Barnabas for the work I have called them to. After some days, even weeks, of further prayer and fasting the church fellowship in Antioch sent them away. What was Saul doing for those 14-17 years? He was separated and studying the Old Testament under the anointing and as the great thinker he was, was able to see through the Old Testament the New Covenant era upon Israel and was able to discuss, teach, argue, in his letters how the New Covenant was directly tied to the Law of Moses, specifically, the Ceremonial Law.
Jeremiah's prophecy of a New Covenant is brief but to the point. Israel was to be forgiven of her sins - past, present, and future - and everything that we find in his letters can be found in the Law of Moses. When Jesus began His Ministry to Israel the religious leaders of the time were in constant conflict with Jesus, but the underlying problem between Jesus and them was that Jesus taught the "spirit of the Law" and the religious leaders only understood the "letter of the Law." Without the Holy Spirit that's all they could understand, and this was a problem also with Saul, until he became born-again and through study under the anointing could see the "spirit of the Law" and this is what he taught in person, and through his letters.