Life Upon Condition of Perfect Obedience

"5. The apostle Paul informs us, That the commandment was ordained to life, "The commandment which was ordained to life, I found to be unto death." By the commandment, as the context plainly shows, is meant the moral law, that  right transcript of the image of Jehovah; which is a system of holy commandments, so intimately connected, and so entirely consistent with each other, as if they had been but one precept. This law, he tells us, "was ordained to life,'' or was unto life. When it was given to mankind, it was given with a promise of life, to all who should yield to it a perfect obedience. Now since it is evident, that the perfect obedience, either of Adam, or of any other mere man, could not by any intrinsic value of its own, merit life for him, at the hand of the infinitely high and holy Jehovah; it follows, that when the law was given with a promise of life, to such as should perfectly obey, it must have been given as a covenant of life; a covenant, according to which the Lord condescended to promise life, upon condition of perfect obedience; saying, "The man which doeth those things, shall live by them." The law could not have secured a title to life, to such as should have performed perfect obedience, if it had not been vested with the form of a covenant of life, for that, as well as for other purposes."

John Colquhoun, A Treatise on the Covenant of Works. page 12.