I can get a little fixated when people dodge and weave.
Paul's prior knowledge remained intact but his perspective had drastically and completely changed from his former beliefs of his keeping the Hebrew laws in order to gain acceptance with God.
Thank you. THAT is the point. St Paul and all of the Apostles taught from the perspective of their Jewish tradition. Jesus didn't abolish the Law, He fulfilled it. It's not that it wasn't holy and of God, just that it was fulfilled and it's strictures were no longer required. Too many people throw the baby out with the bathwater. There is a Jewish history. It is not evil. It is the parent to our own faith. What remained was the essence of the Law which is love of God and man. St Paul was not ashamed to proclaim himself a Pharisee because of his belief in the resurrection. We may no longer be under the strictures of the Mosaic Law... but that doesn't mean it wasn't still instructive for our faith in God and His ways.