That was the basic premise of the Law. Do things pleasing to God and you will become acceptable to God. One does not become righteous by listening, but by doing the works.
In this case +Paul clearly says that the doers of the law will be (not are) justified before God.
"it is not the hearers of the Law who are just before God, but the doers of the Law will be justified." (Rom 2:13)
= = =
A true Scripture. A true statement.
But considering the WHOLE COUNSEL OF GOD IN SCRIPTURE . . .
WHY?
Hebrews and other verses answer that question rather conclusively.
The DOERS OF THE WORD are those with well exercised FAITH INVESTED IN CHRIST'S COVERING; LOVE, SPIRIT TOWARD THE FATHER.