Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin. Therefore we conclude that a man is justified by faith without the deeds of the law. (Romans 3:20, 28)
We who are Jews by nature, and not sinners of the Gentiles, know that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law: for by the works of the law shall no flesh be justified. (Galatians 2:15-16)
For those in Christ, the deeds of the Law have no value!
This objection is both right and wrong. Here's why:
Both the Romans and Galatians passages above are dealing with justification so let's define what justification is.
The New American Standard Exhaustive Concordance of the Bible says justification is "a sentence of acquittal". It is a legal term that says some has been found "not guilty" in a court of law. We are never found "not guilty" before God because we perform the works of the Law. Scripture says all have sinned (Romans 3:23) and so we are all guilty. We are only found "not guilty" because our sinless Messiah is "not guilty" and because of our position under Him.
So in that way, the objection is right. But those who promote this objection try to take it one step further by saying "the deeds of the Law have no value". In this way the objection is wrong.
Just because the deeds of the Law do nothing to justify us before God, that doesn't mean that they have no value. That's like saying "because I cannot eat a shoe, it has no value". You aren't supposed to eat a shoe! That's not what shoes are for! The value of a shoe is determined by its usefulness in achieving its proper purpose: covering and protecting your feet!
So if the Law is not intended to achieve justification (getting a "not guilty" verdict) then what is it for?
The Law of God provides a pattern of living for those who are chosen by God. Living according to the pattern He has established reveals God's character and His glory. When followed properly, the Law is very valuable in achieving its intended purpose.