What power did the law have?
The law had no power to justify or to help even the Jew become a law keeper. Its only function was to condemn and to provide the knowledge or awareness of sin. It could point the finger and declare guilt, but it could not produce righteousness or enable obedience.
Les explains that by the deeds or keeping of the law shall no flesh be justified, for by the law is the knowledge or awareness of sin. The law could do nothing but condemn; it had no power, even to the Jew, to help him be a law keeper. All it could do was point the finger and say you're guilty. But the flip side is the righteousness of God without the law.