I just showed that he taught the Law of Moses. In Psalm 119:29-30, he wanted to put false ways far from him, for God to be gracious to him by teaching him to obey the Law of Moses, and he chose the way of faith by setting it before him, so this has always been the one and only way of salvation by grace through alone.Paul never taught the law of moses. He used it as a starting point to bring his listeners into the knowledge of Jesus saving grace through Faith alone. He was jewish so he kept the customs just like Jesus. But he did not promote it as a nessessity for salvation or a relation with God.
The Hebrew word "yada" refers to intimate relationships/knowledge gained through experience, such as with Genesis 4:1 where Adam knew (yada) Eve, she conceived, and gave birth to Cain. God's way is the way to know (yada) Him and Jesus by experiencing embodying His character traits, which is the narrow way to eternal life (John 17:3). For example, in Genesis 18:19, God knew (yada) Abraham that he would teach his children and those of his household to walk in His way by being doers of righteousness and justice that the Lord might bring to him all that He has promised. In Exodus 33:13, Moses wanted God to be gracious to him by teaching him to walk in His way that he and Israel might know (yada) Him, and in Matthew 7:23, Jesus said that he would tell those who are workers of lawlessness to depart from him because he never knew them, so the goal of the Law of Moses is to graciously teach us how to experience an intimate relationship with God and Jesus, which is His gift of eternal life.