What is natural law?
Ask most people what "natural law" means and they will point to the sense of right and wrong that seems to come built into every human being, before any Bible or commandment reaches them. The commentators treat this carefully, because Scripture speaks both of a moral witness in the conscience and of the fixed order God set running in the physical world — and neither one is quite what popular usage assumes.
The Work of the Law, Not the Law Itself
The exact wording matters. Commentators insist that Scripture never says the law is written on the hearts of people outside Israel — only that the law's work is shown there.
Frederick W GrantThe "law written upon the heart" is only used of Israel's condition when finally converted to God. It is one of the blessings of the new covenant — "I will put My laws in their minds, and write them in their heart" — words which prove conclusively that such a condition is not every man's natural one. While in the passage in Romans often quoted, where at first sight a similar term seems to be applied to the Gentiles, it is in reality a very different one: "Which show," says the apostle, "the work of the law written upon their hearts" — not the law written, but its work. The work of the law is conviction: conscience does this work in the one who has not the law, though far less completely.
In practice this shows up in single acts, not in a whole code known in advance.
William KellyLet a heathen gather somehow the duty of honouring his parents: this, though he may have never heard of the law, is a law to him. So far the work of the law (not the law itself) is said to be written in his heart. His conscience from then on accuses or excuses him according to his conduct; and God in judgment will take all fully into account by and by.
Where Conscience Came From
This inner monitor is not part of humanity as first created. It arrived with the fall, when man took the knowledge of good and evil.
J. N. DarbyAdam was put under a law which required no knowledge in his mind of what was good and evil, or right and wrong in itself. There was no evil in eating the forbidden fruit, except that it was prohibited. It was not good or evil in itself: he acquired the knowledge of good and evil by eating it. The introduction of sin and conscience came together. God did not allow man to go out as a sinner from Paradise to begin this world without carrying a conscience with him. It may have been corrupted — hardened; but it is there to be corrupted and hardened.
The Second Witness: Creation
Alongside conscience stands the visible world. It carries real information about God, but only of a certain kind.
J Wilson SmithWhat is invisible in the Creator should be and is seen, and seen clearly, being understood by the things that are made — even His eternal power and divine nature — not, indeed, His grace, or truth, or love, but infinite power and design, so much so that people are left without excuse. Creation declares the power of God. It does not reveal what He is in Himself — His nature — but to any, except those wilfully blind, it is evidence enough of the existence of a Creator-God.
The Measure of Responsibility
Because conscience and creation give real light, God holds people answerable by them. That is the true function of natural law in Scripture.
The Bible TreasuryHe knows good and evil now, and is therefore responsible on the principle of conscience, or moral discernment, which is in him as possessing that knowledge, even when he has no direct word or revelation from God about himself or his path. Romans 2:5-16 makes it plain that, as regards God's judgment of such men (and those whom we call the "heathen" come within the range of this scripture), that principle becomes the measure of responsibility in their case.
Why It Cannot Save
The popular use of natural law — live by your own light and all will be well — is exactly what the writers reject.
J Wilson Smith"To live up to one's conscience" is a popular idea of the way of salvation! But if conscience should fail to grasp the mind of God, is every sinner who makes a standard of his own individual conscience — his own idea of right and wrong — to find a place in heaven? Truly many heavens would be needed to meet the many different standards of right and wrong.
The failure is not merely that standards vary. The instrument itself is set too low.
A PridhamNatural conscience never rises in its warnings to the measure of Divine requirement.
The Other Sense: Laws in Nature
Used of the physical world, the phrase itself is challenged as misleading.
Morrish Bible DictionaryThere are no laws of nature, as if nature made its own laws: there are laws in nature, which God in His wisdom as Creator was pleased to make; but He who made those laws has surely the same power to suspend them when He pleases.
Summary
- Origin. Conscience entered with the fall; man left Eden a sinner, but carrying a sense of good and evil that can be dulled yet never erased.
- Content. Not the law written on the heart — that is a new covenant promise — but the law's work: conviction, accusing or excusing a man in the deeds he does.
- Reach. Two witnesses go everywhere: conscience within, and creation without, which shows God's eternal power and divine nature, though not His grace or love.
- Result. These fix responsibility. God judges each person by the light he actually had.
- Limit. Natural conscience never rises to God's standard, so living up to it saves no one; light enough to condemn is not light enough to justify.