Kardia #71

Kardia is the ordinary Greek word for the physical heart, but in both the Old and New Testaments it functions as the hub of the whole inner person — thought, will, conscience, and emotion together, not simply the seat of feeling as “heart” tends to suggest in modern English. To speak of the heart in Scripture is usually to speak of who a person really is beneath their outward behavior.

Biblical Usage

Proverbs treats the heart as the wellspring of a person’s whole life, urging, “Keep thy heart with all diligence; for out of it are the issues of life” (Proverbs 4:23), and Jeremiah names its capacity for self-deception bluntly: “The heart is deceitful above all things, and desperately wicked: who can know it?” (Jeremiah 17:9). Jesus identifies love for God with the heart above every other faculty, naming it first in his summary of the greatest commandment: “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind” (Matthew 22:37).

Theological Significance

Paul makes the heart, not merely outward profession, the seat of saving faith: “with the heart man believeth unto righteousness,” while confession with the mouth follows and expresses that inward belief in the risen Lord (Romans 10:9-10). Because kardia names the whole hidden self rather than a single emotion, biblical writers consistently locate the real work of sin and of God’s transforming grace there, treating changed behavior as the fruit of a changed heart rather than the other way around.