Wilhelmus A Brakel, The Christian's Reasonable Service, Vol. 3 pg. 43-44
The Law of the Ten Commandments: Not a Covenant of Works
Question: Is the law of the Ten Commandments a covenant of works?
Answer: No, we shall demonstrate this to be so for the following reasons:
First, God's righteousness cannot permit a sinner to enter into a covenant of friendship without a Surety who bears the punishment of the broken covenant on behalf of the sinner. However, the Israelites were sinners and the Covenant of works is without surety. Thus, the law cannot be a covenant of works.
Secondly, the person with whom God would establish a covenant of works, ought to be able to satisfy the demands of the covenant of works, and to obtain life in consequence thereof, for God's holiness, righteousness, and truth will not permit the establishment of a true covenant upon the basis of a dishonest promise of man...
Thirdly, if the law were a covenant of works, then Israel, and all believers of the New Testament (for they are all under obligation of the law), would simultaneously be in two opposite covenants. They were under the covenant of grace, or else no one could have been saved. "Therefore by the deeds of the Law no flesh will be justified in His sight." (Rom 3:20). And if the the law were a covenant of works, they would be simultaneously under the covenant of grace and the covenant of works. This is Impossible...
Fourthly, if the law were a covenant of works,man would have had to seek salvation by works, for it is thus declared, "For Moses writes that the man who practices the righteousness which is based on law shall live by that righteousness." (Rom 10:5)...
Fifthly, there can be no manifestation of mercy in the covenant of works; however, there is room for mercy in the law of the ten commandments. "but showing mercy to thousands, to those who love Me and keep My commandments." (Ex.20:6). Thus, the law is not the covenant of works.