John Calvin Commentary Jeremiah 12:16

"And it shall come to pass, if they will diligently learn the ways of my people, to swear by my name, As Jehovah liveth; even as they taught my people to swear by Baal; then shall they be built up in the midst of my people." — Jeremiah 12:16 (ASV)

We see that this refers to the Gentiles, who were previously aliens to the grace of God; indeed, they entertained the most dire hatred towards his chosen people.

In short, God declares that he would be merciful and gracious to these miserable nations, for whose salvation no hope was entertained, because they had been rejected by him and had often and long, and in various ways, provoked his vengeance.

And though he speaks of neighbors, as we have seen, yet this prediction belongs generally to the whole world and was finally fulfilled in the call of the Gentiles, for God then gathered a Church indiscriminately from both Jews and Gentiles.

But a condition is here laid down: if the Gentiles, who had previously opposed the true worship of God, received his law. We indeed know how much true religion was hated, especially by the neighboring nations, for their hatred was increased because they saw that their superstitions were condemned by this one people.

Since they had been greatly incensed against God and the pure doctrine of his law, he now requires a change in them. If they will learn, he says, the ways of my people.

By the ways of his people he understands what he had commanded. The people of Israel had indeed often departed from true religion; but God here refers to himself rather than to their perverse conduct, for the law had not been abolished by the wickedness and ingratitude of his people.

Therefore, we see that by the ways of his people, we are not to understand those glosses which the Jews had devised, but the law itself, which God had delivered to them.

The authority of men, therefore, cannot be established from this, as if they had power to frame a religion for themselves; but God means only that by his good pleasure alone the Jews had been taught what was right.

In short, Jeremiah understands the ways of the people passively: not those which the people had contrived for themselves, but such as they had received from above.

It is then added, That they may swear in my name. The expression is a part for the whole, for in it is included the whole worship and service of God.

Swearing, as we have said elsewhere, is a part of God’s worship and of true religion, for we profess that we ourselves and our life are in God’s hand when we swear by his name; and we also refer judgment to him, and own that he is really God, since he knows our hearts and judges of hidden things.

All these things are included in swearing. It is therefore no wonder that, in this place and in many other places, the whole of religion is designated by this expression, according to what is said elsewhere,

Swear shall they all in my name, Live do I, says Jehovah; to me shall bend every knee, and by me shall every tongue swear.
(Isaiah 45:23)

And just as the altar, in another place, signifies the worship of God, so here swearing signifies the same. The meaning is that if the Gentiles became so changed as to submit their neck to the yoke of the law, and allow themselves to be ruled by God, they would be made partakers of the mercy which the Jews had previously enjoyed.

Then follows the common form of swearing, Live does Jehovah. So the Scripture speaks everywhere.

By these words men do not merely testify that they swear by the life of God, but they also ascribe eternity to him, as if it were said, “God alone exists,” for no life is to be found anywhere except in God.

Men, indeed, and brute animals, and even trees, are said to live. But in trees there is only vigor without the senses; in brute animals, the senses without reason and understanding; but in men, life is light.

Yet they do not live by or of themselves, but they derive life from God.

This is similar to what we see on the earth, on which light shines; yet we know that there is really no light where we dwell except what descends and is conveyed to us by the rays of the sun.

In the same manner it may be said that life dwells in men, being conveyed to them by the hidden power of God. Nor do angels, properly speaking, live of themselves.

Therefore, we see the meaning of the words, Live does Jehovah. The eternity of God is set forth by this; he is also acknowledged as the Judge of the world; and further, whatever he claims for himself, men thus testify that it is justly and by right his due.

It afterwards follows, As they taught my people to swear by Baal. The corruptions of the heathen had greatly prevailed among the chosen people; and the greater part, when they saw that the nations prospered, had cast aside every care for true worship and sincere religion.

Since the Jews had been so devoted to the superstitions of the heathen, the Prophet says, speaking in God’s name: If the Gentiles, who have until now taught my people to swear by Baal, who have drawn them away to their own idolatries and fictitious and false forms of worship, begin now to swear by my name, faithfully to worship me alone, they shall be built in the midst of my people.

The metaphor of building is very common. But in this place God intimates nothing more than that the Gentiles would become a part of his flock when they cast away their superstitions and embraced the pure worship prescribed in the law.

This is not to be applied to any particular place, as some have frigidly explained it. Instead, “in the midst of the people,” is the same as if he had said: “I will count those nations my people, as a part of my Church.”

This is according to what is said in the Psalms: that though the Tyrians and Sidonians, Egyptians, and others who had been hostile nations were born here and there, yet they would boast that they were all born at Jerusalem when God acknowledged them as members of his own people (Psalms 138:3, 4).