The heart in Scripture is the totality of the inner person — the seat of thought, will, desire, conscience, and spiritual orientation. It is not primarily the emotions (as in modern usage) but the command center of a human being. What the heart loves determines what the whole person does. Scripture diagnoses the human problem at the heart level: "The heart is deceitful above all things, and desperately sick — who can understand it?" (Jer 17:9). The solution is also at the heart level: the new covenant promise is a heart of flesh replacing a heart of stone (Ezek 36:26). The Shema commands love of God with the whole heart (Deut 6:5). Jesus intensifies this: the commandments are violated at the heart before the act occurs (Matt 5:28). God searches the heart (1 Sam 16:7; Jer 17:10). The heart — not the external performance — is what God sees and judges.
HEART, noun [Saxon heorte; Gr. kardia; L. cor, cordis; W. calon; Ar. heart.]
1. A muscular organ in the chest, which is the primary organ of life and the seat of the affections. In Scripture, the heart is the seat of the understanding, will, and affections. It is used for: the whole inner man; the understanding or reason; the will; the affections and desires; the conscience; courage and resolution.
2. The secret intentions; the purposes; the real meaning: "Their heart is far from me."
3. Disposition of mind; character: "He is a man after God's own heart."
Webster's note: In Hebrew and Greek anthropology, the heart (lev/kardia) encompasses what we would divide into intellect, will, and emotion — it is the unified inner person before God.
• Jeremiah 17:9 — "The heart is deceitful above all things, and desperately sick; who can understand it?"
• Proverbs 4:23 — "Keep your heart with all vigilance, for from it flow the springs of life."
• Ezekiel 36:26 — "I will remove the heart of stone from your flesh and give you a heart of flesh."
• Matthew 5:8 — "Blessed are the pure in heart, for they shall see God."
• Romans 10:10 — "For with the heart one believes and is justified, and with the mouth one confesses and is saved."
H3820 — lev (לֵב): heart; 600+ uses in OT; encompasses mind, will, and feelings — what we would call the whole inner person; God searches it (1 Sam 16:7).
H3824 — levav (לֵבָב): heart (intensive form); used in the Shema (Deut 6:5) — "all your heart" (levavkha) — the doubled form intensifies totality of inner commitment.
G2588 — kardia (καρδία): heart; 160+ uses in NT; in Paul, it is the center of the spiritual life and the site of saving faith (Rom 10:10); in John, it is where Christ dwells by faith (Eph 3:17).
Modern Western culture has reduced "heart" almost entirely to emotion — "follow your heart" means "follow your feelings." This is the precise opposite of the biblical diagnosis. Jeremiah 17:9 teaches that the heart is the most untrustworthy thing about us. "Follow your heart" is sound advice only after Ezekiel 36:26 has occurred — the heart of stone replaced by a heart of flesh through the new birth. An unregenerate heart is deceitful; a regenerate heart is progressively renewed. The therapist's counsel to "listen to your heart" and the preacher's counsel to "guard your heart" (Prov 4:23) are not compatible unless one understands which heart, at what stage of redemption, is being addressed.
PIE root *kerd- = heart
Latin: cor, cordis → courage (coeur), record (re + cor = "bring back to heart"),
cordial, concord, discord
Greek: kardia → cardiac, cardiogram
Germanic: heorte → heart, hearty
Hebrew לֵב (lev, H3820)
Not clearly derived from a verbal root; the heart is fundamental, not derived
Used for: understanding ("he has no heart" = he lacks sense, Prov 6:32)
will ("the heart said" = the person decided)
emotion (the heart "melts" in fear)
worship ("with all your heart" = total inner devotion)
The ancient Hebrew person was not divided into reason/emotion/will
— these were unified in the heart.
Biblical anthropology is holistic: the whole inner person before God.
• "Jeremiah 17:9 — the heart is not your compass. It's your cancer. Until the new birth, the very organ you're supposed to navigate by is the one most profoundly broken."
• "God looked at David and saw the heart (1 Sam 16:7). Everything else Samuel saw was impressive. What God saw was what no one else could see. You can fool everyone but God."
• "The new covenant promise is a heart transplant (Ezek 36:26). Not heart surgery — heart replacement. The old heart doesn't get improved; it gets exchanged."