"The law of creation requires man to perform perfect obedience and says, 'Do.' But the law as a covenant of works requires him to 'do and live'; to do, as the condition of life; to do, in order to acquire by his obedience a title to life eternal.
The command to perform perfect obedience merely is not the covenant of works, for man was and is immutably and eternally bound to yield perfect obedience to the law of creation though a covenant of works had never been made with him.
But the form of the command in the covenant of works is perfect obedience as the condition of life. The law in this form comprised not only all the commandments peculiar to it as the Law of nature but also a positive precept that depended entirely on the will of God:
'The LORD God commanded the man, saying, Of every tree of the garden thou mayest freely eat: but of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die' (Gen. 2:16-17).
This positive precept was, in effect, a summary of all the commands of the natural or moral law; obedience to it included obedience to them all, and disobedience to it was a transgression of them all at once. The covenant of works, accordingly, could not have been broken otherwise than by transgressing that positive precept...
For though the law in its covenant form is broken, yet it is far from being repealed or set aside. The obligation of this covenant continues in all its force, in time and through eternity, on every sinner who is not released from it by God, the other party. The awful consequence is that every unregenerate sinner is bound at once to perform perfect obedience and also to endure the full execution of the penal sanction.
The preceptive part of that divine contract continues to bind both by its original authority and by mans consent to it, which consent is no more his to recall, except he is freed from his obligation by the other contracting party. And now that the curse of the covenant is, in consequence of transgression, become absolute, it binds as strongly as even the precept.
The law, then, as a covenant of works, does, in the most authoritative manner, demand from every descendant of Adam who is under it perfect holiness of nature, perfect righteousness of life, and complete satisfaction for sin. And none of the race of fallen Adam can ever enter heaven unless he either answers these three demands perfectly in his own person or accepts by faith the consummate righteousness of the second Adam, who 'is the end of the law for righteousness to every one that believeth" (Rom. 10:4)."