Christ came to fulfill the Law.
In part, He did “away” with it by returning us to the simple faith of Abraham. He did not know the Law, but knew God.
However, you must retain the Old Testament for Christ to have any relevance.
Old Testament persons most definitely knew what was immoral or against God before the Law. Even Adam and Eve understood.
The New Testament requires the Old.
I disagree respectfully. It is clearly not relevant after the new covenant. The new covenant is “if you believe in my Son, you are forgiven”. If you don’t , you go to the grave and dust.