What does it mean that the law is written on our hearts (Romans 2:15)?

It is argued by some who would neutralize these differences, that Gentiles are said to have the law written in their hearts. Why not look into what the apostle actually says and means, instead of twisting a few words into a contradiction of his express doctrine? It would be strange indeed, and say but little for Christianity, if heathens possessed as such that which the Epistle to the Hebrews (Heb. 10:15-16.) affirms to be one of the grand and distinctive blessings of the New Covenant. This kind of theology teaches that the heathen have already the law written in their hearts. But the apostle does not stultify himself, as this would imply, — does not predicate of the heathen that immense mercy of God which the New Covenant holds out to faith based on redemption in Christ. What he really teaches is that whenever (for indeed it was scanty and rare) Gentiles do by nature the things of the law, they evince the law's work written in their hearts. He says not that the law, as these uninstructed men assume, but that its work, was written therein. For instance, let 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 thenceforth accuses or excuses him according to his conduct; and God in judgment will take all fully into account by and by. But this in no way interferes with the opening principle that some sin without being under law and so perish, as others more guiltily sin under law, and so shall be judged; for the question in judgment is not privilege but fidelity according to what we know or may know. Not the law-hearers are just with God but the law-doers shall be justified. This is invariably true; as scripture declares, faith accepts and judgment will display.

To establish its universality, they have had to distinguish between a written and an unwritten law; or, as they assume to call it from Scripture, a law written on the heart. What they mean is in fact conscience, an implicit law which every one has, while the ten commandments are only its explicit form, and as such given to Israel alone. In the same way they prove equally, as they think, its existence from the beginning.

Scripture refuses this, however, utterly. The "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 written, as the original text declares without any question. The work of the law is conviction: conscience does this work in the one who has not the law, though far less completely: "By the law is the knowledge of sin;" and this knowledge conscience in measure gives to every one, and in that respect they, "having no law" (so the Revised Version correctly gives it), "are a law unto themselves." Had they a law, they would not be a law to themselves.

“Which show the work of the law written in their hearts.” It is certainly not the law itself written in their hearts, but the law's work. And there is surely little difficulty in seeing that the law's work — its very purpose — is to bring sin to remembrance, to convict the heart and conscience of sin. See Rom. 3:20. Even those without law have a conscience that bear witness to their sin, while their ability to judge others and their attempts to cover their own sin by excuses, only more fully exposes them. It is a true exposure of man's natural reasoning as regards sin, in whatever state or circumstance he may be; their thoughts accuse or else excuse one another. Either they assume a hard, legal spirit on account of the sins of others, or else a lightness that glosses it over with excuses. But accusation will not atone for sin, nor will excuses put it away. Is there no other attitude toward one who has sinned? Ah yes, indeed, the only one of true value and of pure motives. Do we pray for such as this? — pray from a heart touched and compassionate toward the one who has so dishonored God? Surely this will leave a spirit neither accusing nor light and flippant at the thought of the sins of others. It will lead me more thoroughly and honorably to judge myself and to seek with deepest meekness that the other may also judge his own sin. For God can put sin away, while all my accusing or excusing is shallow, wretched vanity.

The apostle states, that in these particular instances, in which the Gentiles did the things contained in the law, they shew the work of the law written in their hearts. The law is not said to be written there, but that particular act which the law required was shewn to be upon their conscience. For when the Gentiles who have not law (it is not the law at all) do by nature* the things of the law, these, not having law, are a law to themselves, which shew the work of the law written in their hearts. Written agreeing with work, not with law at all. These are the only words in which the law is said to be written on the heart, an expression which ought in itself to have awakened suspicion in one acquainted with the truth. The expression, "law written on the heart by nature," is surely one which should startle anyone who knew the truth of God. Dr. Wardlaw gets out of this difficulty by saying nature does not exclude grace, and that the law could be known responsibly without any subjection or conformity to it. It is a laborious effort for which the statement gives no occasion. The force of the sentence is, that there was something written proved by the deed done.

We are not safe in putting limitations upon God. I quite agree there is a danger of our doing it. We read in Romans 2:14, "For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves; which show the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the meanwhile accusing or excusing one another". Paul is referring to the Gentiles who had no law whatsoever, and yet had the testimony of creation. Apparently there were those who evidenced the work of the law written in their hearts, although they had never heard of the law which was written by Moses.

(Vv. 13-15) Verses 13-15 form a parenthesis showing, Firstly, it would be useless for Jewish moralists to plead they have heard the law; the question is are they doers of the law? "Hearing" would not justify, but "doing"; and none have kept the law. Secondly, it would be useless for the Gentile moralists to plead they have not the law, for, as a matter of fact the Gentile requires no law to tell him not to murder, nor steal, nor bear false witness. His own nature tells him these things are wrong, and therefore he is a law to himself. The fact that we know these things to be wrong shows clearly that the "works" that the law requires are written in our hearts. This is the knowledge of good and evil acquired at the fall and that all men possess. This knowledge may vary, but all men possess some measure of light as to good and evil.

Furthermore, not only have all men a measure of light, they have also a conscience which bears witness according to the measure of light possessed. Conscience is not the light, and therefore is no guide. The compass will not guide the ship; only the rudder will guide under the control of the helmsman. But the compass will tell the helmsman directly he is off the course; so conscience will bear witness directly we cease to walk according to the light we have. Then the mind acts either by listening to, or stifling, conscience — accusing or excusing.

The parenthesis shows us that many things which the law demanded were of such a nature that men knew they were wrong in their hearts without any law being given. And further men had the warning voice of conscience as to these things even when they had no knowledge of the law of Moses. Go where you will you find that men, even the most degraded, have a certain amount of natural light or instinct as to things that are right or wrong. Also they have conscience, and thoughts which either accuse or excuse. Hence there is a ground of judgment against them apart from the law.

The Gentiles, though they never received the law, yet had consciences. Sin was sinful even before the law came. Natural conscience accuses a man of sin, if he kills another; even if he never heard of the ten commandments. This shows that the work of the law — its moral demand — is in every man's conscience. Sin is everywhere sinful to God, law or no law. And men will be judged according to God's thoughts of sin when the day arrives. He will judge the Secrets of men. Oh, how solemn! (vv. 14-16).

All the world then, during that long period, was in the state of "the Gentiles which have not the law;" yet, even so, there were among them those who at times did "by nature the things contained in the law" when it arrived, They reverenced God, as Job, and obeyed their parents, as Isaac, and thus doing, they showed "the work of the law" (mark not "the law," but its work) "written on their hearts;" to wit, the operation of conscience (Rom. 2:14-15).

Does this then justify the Jew in his thought of a different issue as to himself from the condemnation which he readily accords to the Gentile? The apostle's purpose in all this is one quite opposite: it is to bring in all men guilty before God. And here he goes on to show that a Gentile may be comparatively in a better position than the Jew. The law does not justify hearers (in which case a Jew might indeed congratulate himself) but doers: "the doers of the law shall be justified." By and by we shall hear the sweeping sentence of the law as to all, and that "by works of law shall no flesh be justified in [God's] sight: for by the law is the knowledge of sin." Here he does not as yet say this; but he appeals to the conscience of the Jew, priding himself upon the mere knowledge and possession of that which he had no care to keep, against any comparison of himself with the lawless Gentile such as he was prone to make. "For when the Gentiles who have no law practise by nature the things of the law, these, having no law, are a law unto themselves, being such as show the law's work written in their hearts, their conscience bearing witness therewith, and their thoughts one with another accusing or else excusing."

We must distinguish carefully in these words "the law's work written in the heart" of a Gentile, from the law written in the heart of a converted Israelite, according to the new covenant (Heb. 8:10). The confusion here is only part of a system widely held, which would, in direct contradiction to the words of the apostle here, put the whole of mankind from the beginning, with Adam their first father also, under the law of Moses, writing up, "This do, and thou shalt live" over the gate of heaven, and bringing in Christ as also under law, to do that which Adam failed to do, and justify us by His obedience in life, rather than solely "by His blood," as this epistle teaches. It would take us far out of our way to examine this at the present time, and anticipate that which will come in the scriptural order before us, as we proceed with our subject. As to the point now, the Greek shows conclusively, as our common English version does not, that it is the "work" that is said to be written, not the law itself. The Gentile here is said to have — that is, to be under — no law. It is only put in another form when it is said that he is a law to himself: he defines for himself what his duty is; (it does not mean, of course, that he has none, or has no thought of any, but) he has to gather the intimations of it from his own moral instincts or from his observations of others about him, perhaps also learns by more direct teaching; but precisely the thing which is lacking to him is that code of authoritative precepts which the Jew had in the law. As a law to himself, he recognized himself as under authority, as the Jew did, and under divine authority, for that is all that the apostle has in view, as is plain, just now; but he is under no yoke imposed by God as the Jew was; whatever be the cause of it (which we have seen in part, but which we are not investigating here,) he is a man left to himself. Yet there is that in him which does the work which the law was designed to do in giving the knowledge of sin (Rom. 3:20); not indeed in the perfect manner of the law, yet so that he who listens to the inward monitor may well condemn the Jew with his higher privilege and his lower practice.