John Calvin Commentary Jeremiah 31:33

"But this is the covenant that I will make with the house of Israel after those days, saith Jehovah: I will put my law in their inward parts, and in their heart will I write it; and I will be their God, and they shall be my people:" — Jeremiah 31:33 (ASV)

He now shows a difference between the Law and the Gospel, for the Gospel brings with it the grace of regeneration; its doctrine, therefore, is not that of the letter, but penetrates into the heart and reforms all the inward faculties, so that obedience is rendered to the righteousness of God.

A question may, however, be raised here: Was the grace of regeneration lacking to the Fathers under the Law? But this is quite preposterous. What, then, is meant when God denies here that the Law was written on the heart before the coming of Christ? To this I answer that the Fathers, who were formerly regenerated, obtained this favor through Christ, so that we may say that it was, as it were, transferred to them from another source.

The power then to penetrate into the heart was not inherent in the Law, but it was a benefit transferred to the Law from the Gospel. This is one thing. Then we know that this grace of God was rare and little known under the Law; but that under the Gospel the gifts of the Spirit have been more abundantly poured forth, and that God has dealt more bountifully with his Church.

But still, the main thing is to consider what the Law is in itself and what is peculiar to the Gospel, especially when a comparison is made between the Law and the Gospel.

For when this comparison ceases, this cannot be properly applied to the Law. But with regard to the Gospel, it is said that the Law is that of the letter, as it is called elsewhere (Romans 7:6), and this is also the reason why Paul calls it the letter in 2 Corinthians 3:6:

“the letter killeth,”

etc. By “letter” he does not mean what Origen foolishly explained, for Origen perverted that passage as he did almost the whole Scripture.

Paul does not mean there the simple and plain sense of the Law. He calls it the letter for another reason: because it only sets before the eyes of people what is right and sounds it also in their ears.

And the word letter refers to what is written, as if he had said, the Law was written on stones and was therefore a letter.

But the Gospel—what is it? It is spirit. That is, God not only addresses his word to the ears of men and sets it before their eyes, but he also inwardly teaches their hearts and minds.

This, then, is the solution to the question: the Prophet speaks of the Law in itself, as apart from the Gospel, for the Law then is dead and destitute of the Spirit of regeneration.

He afterward says, I will put my Law in their inward parts. By these words he confirms what we have said: that the newness, which he mentioned before, was not in substance, but only in form.

For God does not say here, “I will give you another Law,” but I will write my Law—that is, the same Law which had formerly been delivered to the Fathers.

He then does not promise anything different regarding the essence of the doctrine, but he makes the difference only in the form. He states the same thing in two ways, saying that he would put his law in their inward parts, and that he would write it in their hearts.

We indeed know how difficult it is for a person to be so formed to obedience that his whole life may be in unison with the Law of God, for all the lusts of the flesh are so many enemies, as Paul says, who fight against God (Romans 8:7).

Since, then, all our affections and lusts carry on war with God, it is in a sense a renovation of the world when people allow themselves to be ruled by God.

And we know what Scripture says: that we cannot be the disciples of Christ unless we renounce ourselves and the world, and deny our own selves (Matthew 6:24; Luke 14:26, 27).

This is the reason why the Prophet was not satisfied with one statement, but said, I will put my Law in their inward parts, I will write it in their hearts.

We may further learn from this passage how foolish the Papists are in their conceit about free will. They indeed acknowledge that without the help of God’s grace we are not capable of fulfilling the Law, and thus they concede something to the aid of grace and of the Spirit; but still, they not only imagine a co-operation of free will, but ascribe to it the main work.

Now the Prophet here testifies that it is the unique work of God to write his Law in our hearts. Since God then declares that this favor is rightfully his, and claims the glory of it for himself, how great must be the arrogance of people to appropriate this to themselves?

To write the Law in the heart imports nothing less than to form the heart in such a way that the Law rules there, and that there is no feeling of the heart that is not conformable to and does not consent to its doctrine.

It is therefore sufficiently clear that no one can be turned to obey the Law until he is regenerated by the Spirit of God.

Indeed, there is no inclination in a person to act rightly unless God prepares his heart by his grace.

In a word, the doctrine of the letter is always dead until God vivifies it by his Spirit.

He adds, And I will be to them a God, and they shall be to me a people. Here God generally encompasses the substance of his covenant; for what is the design of the Law, other than that the people should call upon him and that he should also care for his people?

For whenever God declares that he will be our God, he offers to us his paternal love and declares that our salvation has become the object of his care. He gives us free access to himself, bids us to rely on his grace, and, in short, this promise contains in itself everything necessary for our salvation.

The case is also the same today under the Gospel, for as we are aliens from the kingdom of heaven, he reconciles us to himself by it and testifies that he will be our God.

On this depends what follows: And they shall be my people; for the one cannot be separated from the other.

By these words, then, the Prophet briefly intimates that the main purpose of God’s covenant is that he should become our Father, from whom we are to seek and expect salvation, and that we should also become his people.

More is to be said about these things later, but I have explained the reason why I am now so quickly passing over matters worthy of a longer explanation.

He adds, —