John Calvin Commentary Jeremiah 17:9-10

"The heart is deceitful above all things, and it is exceedingly corrupt: who can know it? I, Jehovah, search the mind, I try the heart, even to give every man according to his ways, according to the fruit of his doings." — Jeremiah 17:9-10 (ASV)

What is taught here depends on what has gone before, and therefore they should be read together. Many take hold of these words and mutilate them without understanding the Prophet's design. This is very absurd, for we should first see what the prophets had in view, by what necessity or cause they were led to speak, what their condition was, and then the general doctrine that may be gathered from their words.

If we wish to read the prophets with benefit, we must first consider the reason why a thing is spoken, and then elicit a general doctrine. Thus we shall be able to rightly apply this passage to common use, if we first understand why the Prophet said that the heart of man was insidious.

He wished, no doubt, to be more earnest with the Jews, for he saw that they had so much rebelliousness and obstinacy that a simple and plain doctrine would not have penetrated into their hearts. The declaration that they are accursed who trust in men, and that no blessedness can be expected unless we rely on God, should have been sufficient to move them. But when he saw that there was no sufficient power in such a declaration, he added, “I see how it is; the heart is wicked and vicious. So you think that you have so much craftiness that you can mock God and His ministers with impunity. I, says Jehovah, I will inquire and search, for it belongs to Me to examine the hearts of men.”

We therefore see that there is an implied rebuke when he says that the heart is insidious and wicked, as if he had said, “You think yourselves wise in this instance; is not God also wise?” Isaiah says ironically the same: “Woe to them who go down to Egypt and make secret covenants, and who trust in horses, as though they could deceive me: ye are wise, I also have a portion of wisdom” (Isaiah 31:1).

Notice especially the expression, “Ye are wise, etc.;” that is, “You are not alone wise; leave to Me some portions of wisdom, so that I may be wise like yourselves.” So also in this place, “You are deceitful and insidious, and think that I can be deceived,” for astute men are always pleased with their own plans and seek to deceive God with mere trifles. “You are,” he says, “very cunning; but I, Jehovah, will search both your hearts and your reins.” I cannot finish the whole today.

Prayer:

Grant, Almighty God, that as we are wholly nothing and less than nothing, we may know our nothingness. Having cast away all confidence in the world as well as in ourselves, may we learn to flee to You as suppliants and so put our trust in You for our present life and for eternal salvation, that You alone may be glorified. May we be devoted to You through the whole course of our life, and so persevere in humility and in calling on Your name, that You may not only bring us help once, but that we may know that You are always present with those who truly and from the heart call upon You, until we shall at last be filled with the fullness of all those blessings which are laid up for us in heaven by Christ our Lord — Amen.

[Exposition continues from previous day's lecture]

We began yesterday to explain that passage where the Prophet says that the heart is insidious, or fallacious and wicked, so that no one can penetrate into those deceits which are concealed within it. We referred to the Prophet’s purpose in saying this—that the Jews might know that their cunning was in vain while they hid their thoughts, as it were, under the earth; that is, while they thought that by their false pretenses they could deceive God as well as men.

He says then what he takes as granted: “I know that you have a fallacious heart.” This indeed they did not allow, for they made a specious pretext and boasted of their wisdom, and not of deceit and guile. But the Prophet speaks plainly and expresses the fact as it was: “There is in you,” he says, “a fallacious and a wicked heart. Hence is the confidence which inebriates you, for you think that your deceits cannot be discovered.”

Then in astonishment he asks, Who can search it? But the answer immediately follows, I — I Jehovah; that is, “It belongs to One to search the heart and the reins, and so nothing can escape Me.”

The meaning then is that when men try to deceive God, they gain nothing, for God knows how to take the wise in their own craftiness and to discover all their guiles and deceits. Then He adds for what purpose this is done: That I may render to every one according to his ways, according to the fruit of his works.

By these words he means that they, after having for a long time made many evasions, would nevertheless be brought to judgment, willing or unwilling. For they could not possibly deprive God of His right to be the judge of the world and thus render to each the reward of his own works.

For the Prophet does not speak of merits or of virtues, but only shows that however much the ungodly might hide themselves, they could not yet escape the tribunal of God, but that they must at last render an account to Him.

We may further gather from this passage a general truth—that the recesses of the heart are so hidden that no judgment of a person can be formed by any human being. We indeed know that there are appearances of virtue in many, but it belongs to God alone to search the hearts of men and to try the reins. Many, then, rashly form an estimate of man’s character according to their own perceptions or the measure of their own knowledge, for the human heart is always false and deceitful. If anyone objects and says that Jeremiah speaks of the Jews then living, there is an answer given by Paul: “Whatsoever things are written in the Law pertain to all” (Romans 15:4).

Thus, what is described here is the character of all mankind, until God regenerates His elect. As then there is no purity except from the Spirit of God, as long as men continue in their own nature, their hearts are full of deceits and frauds. So the fairest splendor is nothing but hypocrisy, which is abominable in the sight of God. Let us proceed—