John Calvin Commentary Jeremiah 29:9

"For they prophesy falsely unto you in my name: I have not sent them, saith Jehovah." — Jeremiah 29:9 (ASV)

He confirms what he had said with this reason: that they ran without being called, according to what we found in Jeremiah 23:21. He then repudiates these false prophets, because they did not speak from the mouth of God.

But the difference was rendered very obscure and indistinct when they pompously alleged the name of God and professed that they brought forward nothing but what they had learned from Him. Yet, as we have said elsewhere, no one can be deceived except willingly and knowingly, for God never leaves His faithful people destitute of the spirit of discernment, provided they offer themselves cordially and sincerely to be taught by His true and legitimate servants.

The Jews then should have examined all the doctrines and all the prophecies by the rule of the Law. If the Law was difficult to understand, they should, as I have said, have sought from God the spirit of wisdom and discernment.

Jeremiah then did not reject without reason whatever the false prophets boasted of for the purpose of gaining the approval and applause of the people, for they were not sent nor approved by God.

So also today, everyone who wishes to distinguish with certainty between various doctrines by which the world is agitated, even shaken, can achieve his goal without difficulty, provided he offers himself as a scholar to Christ, connects the Law and the Prophets with the Gospel, and uses this rule to test all doctrines. It is also provided that, in the meantime, he does not trust his own acumen, but submits himself to God and seeks from Him the spirit of judgment and discrimination.

It should also be noted that in the same way, the false prophets can be abundantly exposed when we thus show that they are not sent by God. We further convict them of vanity when we prove their doctrine is inconsistent with the Law and the Gospel.

However this may be, this principle should be maintained: no one should be heeded but those who can show that they bring messages from God and are equipped with His word.

We have said elsewhere that for anyone to be accounted as sent by God, two things are necessary:

1. That he should be rightly called.
2. That he should faithfully execute his office.

For whoever thrusts himself in without the command of God, though he may speak what is true and holy, yet does not deserve the name of a prophet or teacher. Vocation itself will not be sufficient, unless there is faithfulness and integrity.

But what Jeremiah mainly insists on here is that those who promised the people a return in a short time did not speak from the mouth of God: They prophesy falsely, he says, in my name; how? Because I have not sent them.