"Know ye not, brethren, (for I speak to them that know the law,) how that the law hath dominion over a man as long as he liveth?" (Rom 7:1)
Here is an actual Scripture with Paul talking directly to them that know the law. But he was not just talking to the Jews.
Paul is not referring to his 'brethren' the Jews. He is referring to us, his brethren in Christ Jesus.
"Wherefore, my brethren, ye also are become dead to the law by the body of Christ." (vs 4)
God is speaking to us, His people, even as He makes a direct comment to those who know the law. Which point of law from the Old Covenant is now quoted as point of Law in the New. Any reader now knows enough of the Law to understand what God is talking about pertaining to His New Covenant. Knowing either the whole law or any Jewish traditions based on that law is entirely unnecessary to fully understand what Jesus is saying to His people, His brethren, among whom He is the firstborn. (Rom 8:12)
The one and only time Paul refers to the Jews, his kinsmen after the flesh, as 'brethren', is when he states that plainly (Rom 9:3). And when he does so, he is not even talking to them as a special people, but about them as specially blind.
All Scripture is specifically written to God's people for the benefit of God's people, first the Jews in the Old Covenant, and now the Christians in the New. And the traditions made by the Jews out of the Old were just as invalid and destructive to faith of God as those made by Christians out of the New.
The best and wisest course of reading and understanding Scripture, is to stick with Scripture only, and let God reveal Himself and His Word perfectly by His Scripture read plainly and simply. And leave the garbage of men's traditions and minds out of it, and including our own, if Scripture does not prove it as so. (Acts 17)
The Bereans were more noble than the Jews that rejected Jesus, because they went to the Scriptures to see if what Paul said was true, and they did not go to tradition to help confirm and understand it better.