The Searcher of Hearts
Jeremiah declares that YHWH searches the heart and renders to each according to his deeds. Revelation 2:23 places this searching knowledge and judicial authority in the declaration of the risen Christ. This study examines the striking **similarity** between these passages and its Christological significance.
Jeremiah 17:9–10 and the Judgment of Christ in Revelation 2:23
“I the LORD search the heart and test the reins, to give every man according to his ways, according to the fruit of his deeds.”
— Jeremiah 17:10
The Hidden Heart
Jeremiah 17 sets before the reader a contrast between misplaced confidence in man and confidence in YHWH. The man who trusts in flesh is likened to a shrub in the desert, whereas the man who trusts in YHWH is compared to a tree planted by waters (Jeremiah 17:5–8).
The prophet then turns from outward conduct to the inward condition from which it proceeds: “The heart is deceitful above all things, and desperately sick; who can understand it?” (Jeremiah 17:9).
The Hebrew lēb, “heart,” denotes more than emotion. It may encompass thought, intention, desire, and will. The adjective ʿāqōb, “deceitful,” describes that which is crooked or treacherous, while ʾānuš denotes a condition grievously afflicted or beyond ordinary remedy. Jeremiah's question, “Who can understand it?”, therefore concerns the inability of man to discern fully the concealed purposes of the heart.
Verse 10 supplies the answer:
“I the LORD search the heart and test the reins, to give every man according to his ways, according to the fruit of his deeds.”
The verb ḥāqar signifies searching or examining thoroughly, while bāḥan denotes testing or proving. The “reins,” or kidneys (kəlāyôt), belong to the biblical language of the inward parts and are frequently associated with the deepest affections and purposes of a person. Heart and reins together thus describe the inward man as the object of divine examination.
The purpose of this examination is expressly judicial. YHWH searches the heart and tests the reins “to give every man according to his ways, according to the fruit of his deeds.” Knowledge of the inward man and judgment of his deeds are joined in a single declaration. YHWH knows what man cannot know and judges on the basis of that perfect knowledge.^1
YHWH Who Knows the Heart
The language of Jeremiah belongs to a wider testimony of Israel's Scriptures.
When Samuel looks upon Eliab and supposes that the LORD's anointed stands before him, YHWH corrects the judgment of the prophet: “Man looks on the outward appearance, but the LORD looks on the heart” (1 Samuel 16:7). The distinction is plain. Man sees the visible form; YHWH sees the heart.
The same truth appears with particular force in Solomon's prayer at the dedication of the temple:
“Render to each whose heart you know, according to all his ways, for you, you alone, know the hearts of all the children of mankind” (1 Kings 8:39).
The words “you alone” (ʾattâ ... ləbaddəkā) are especially important. Knowledge of the hearts of all men is here ascribed to YHWH alone.
The Psalms speak in the same manner. Psalm 7 appeals to the righteous God who tests “the hearts and reins” (Psalm 7:9). Psalm 139 begins, “O LORD, you have searched me and known me,” and proceeds to describe a knowledge extending to thought, speech, movement, and the secret formation of the person.
Jeremiah himself elsewhere addresses YHWH as the one who “tests the righteous” and sees “the reins and the heart” (Jeremiah 11:20; Jeremiah 20:12). The prophet's appeal depends upon the certainty that no inward motive is concealed from the divine judge.
Jeremiah 17:10 therefore stands within a well-attested scriptural usage. YHWH knows the heart, examines the inward parts, and judges man with a knowledge unavailable to human sight.
The Greek Text and the Johannine Witness
The Septuagint renders Jeremiah 17:10:
egō kyrios etazōn kardias kai dokimazōn nephrous
“I the Lord search hearts and test reins.”
The Greek preserves both parts of the Hebrew expression. Kardiai are hearts; nephroi, literally kidneys, represent the reins or inward parts. The verbs etazō and dokimazō express examination and testing.
Romans 8:27 employs related language when Paul speaks of God as ho ereunōn tas kardias, “the one who searches the hearts.” Of particular importance is the verb ereunaō, “to search,” for the same verb occurs in the declaration of Christ in Revelation 2:23.
The Gospel of John also attributes remarkable knowledge of man to Jesus. John writes that Jesus “knew all people and needed no one to bear witness about man, for he himself knew what was in man” (John 2:24–25). The evangelist does not explain the ground of this knowledge. His statement concerns the fact itself: Jesus requires no human testimony concerning what is in man.
At the close of the Gospel, Peter makes a similar appeal. Grieved by the third question, “Do you love me?”, Peter answers, “Lord, you know all things; you know that I love you” (John 21:17). Peter rests his appeal upon the knowledge of Christ, confident that the truth of his affection is known to him.
These passages do not by themselves determine the meaning of Revelation 2:23. They do, however, show that the knowledge of what lies within man is already an important feature of the Johannine presentation of Jesus.
The Son of God Who Searches Reins and Hearts
The declaration in Revelation 2 occurs in the address to the church at Thyatira. The speaker is introduced as “the Son of God, who has eyes like a flame of fire, and whose feet are like burnished bronze” (Revelation 2:18).
The description is suited to what follows. Christ knows the works of the church (Revelation 2:19), condemns its toleration of the woman called Jezebel (Revelation 2:20), declares that he has given her time to repent (Revelation 2:21), and announces judgment upon her and those who participate in her deeds (Revelation 2:22–23).
The judgment reaches its explanation in verse 23:
“And all the churches will know that I am he who searches reins and hearts, and I will give to each of you according to your works.”
The Greek reads:
egō eimi ho ereunōn nephrous kai kardias
“I am the one who searches reins and hearts.”
The resemblance to Jeremiah 17:10 is considerable, though the words are not identical. Jeremiah in the Septuagint employs etazō and dokimazō, whereas Revelation employs ereunaō. The order of “hearts” and “reins” is also reversed. Revelation 2:23 should therefore not be described as a verbatim citation of the Greek Jeremiah.
The similarity lies chiefly in the union of inward examination and judicial recompense.
In Jeremiah, YHWH searches the heart and tests the reins in order to give to each according to his ways and deeds.
In Revelation, Christ searches the reins and hearts and gives to each according to his works.
The second clause is indispensable to the comparison. The resemblance does not consist merely in knowledge of the inward man. In both passages, the one who examines what is hidden also renders judgment according to human conduct.^2
The expression egō eimi should likewise be interpreted according to its grammar. Here it is followed by the articular participle ho ereunōn, “the one who searches.” It is therefore not an absolute use of egō eimi. The force of the saying does not depend upon treating the words “I am” as an independent divine formula. Attention belongs instead to what Christ says that he is: the one who searches reins and hearts.
The Searcher and the Judge
Read beside Jeremiah 17:10, the significance of Revelation 2:23 becomes apparent. The risen Christ does not merely claim knowledge of the churches' outward works. His knowledge reaches the inward parts, and his judgment proceeds from that knowledge. The grammatical subject remains the same: the one who searches is the one who recompenses.
The churches will know him as the searcher of reins and hearts precisely through the judgment that he executes. The declaration therefore joins knowledge of what is hidden with authority to repay according to works.
This language is especially noteworthy in light of the scriptural testimony already considered. Solomon confesses that YHWH alone knows the hearts of all men. Jeremiah declares that YHWH searches the heart and tests the reins in order to render according to man's deeds. Revelation places this declaration upon the lips of the risen Son of God.
The passage does not itself set forth a systematic account of the relation between the Son and YHWH, and its language should not be made to answer questions beyond its immediate purpose. Yet neither should the connection be diminished. Revelation presents Christ as personally exercising toward the churches the searching knowledge and judicial recompense which Jeremiah ascribes to YHWH.
The Christological significance lies in that fact.
Conclusion
Jeremiah ascribes to YHWH the searching of the hidden heart and the rendering of judgment according to deeds. Revelation places this shared pattern of inward examination and judicial recompense in the declaration of the risen Christ. The textual evidence should be allowed its full weight without requiring the text to say more than it says.
The risen Christ stands among the churches as the searcher of reins and hearts and the judge who renders to each according to his works.
Footnotes
William L. Holladay, Jeremiah 1: A Commentary on the Book of the Prophet Jeremiah, Chapters 1–25 (Philadelphia: Fortress Press, 1986).
David E. Aune, Revelation 1–5, Word Biblical Commentary 52A (Dallas: Word Books, 1997).