Word studies · Greek · Strong's G2588
καρδία · kardía · appears 161 times in the New Testament
In one line: The inner self — mind, will and affections together.
Blessed are the pure in heart, for they will see God.
Matthew 5:8
Kardia is the heart as the control center of a person — thinking, willing and feeling together, not emotion alone.
In the New Testament the heart is where a person believes, reasons, doubts, decides and hides things: people “ponder in their heart,” “believe in the heart,” and are exposed as those whose heart is far from God. It names the inner self as a whole, out of which conduct comes.
Kardia is the ordinary Greek word for the bodily organ, extended figuratively — and the Septuagint used it to translate Hebrew leb, which already carried the full range of mind, will and emotion. So the New Testament inherits a Hebrew way of thinking wearing Greek clothes.
Modern English opposes the head to the heart, feeling to thinking. Scripture makes no such split: the heart is exactly where thought happens, which is why Jesus can say “out of the heart come evil thoughts” and Paul can speak of the eyes of the heart being enlightened.
Kardia (G2588) appears 161 times in the New Testament and gives English “cardiac” — while the Latin cor behind it stands behind “courage” and “record.”
If the heart is the whole inner person, then God's requirement and God's work both go all the way down: He promises a new heart rather than better behavior, and Jesus locates purity and defilement alike inside rather than at the surface. It is also why “believe in your heart” is not sentiment but the commitment of the self.
Notice the gap between what you say you believe and what you actually decide under pressure — the second is your heart. Bring one such gap to God today and ask Him to change you at that level rather than to help you perform better.
the heart, i.e. (figuratively) the thoughts or feelings (mind); also (by analogy) the middle
But some of the scribes were sitting there and thinking in their hearts,
Mark 2:6And he will go on before the Lord in the spirit and power of Elijah, to turn the hearts of the fathers to their children and the disobedient to the wisdom of the righteous—to make ready a people prepared for the Lord.
Luke 1:17“He has blinded their eyes and hardened their hearts, so that they cannot see with their eyes, and understand with their hearts, and turn, and I would heal them.”
John 12:40Therefore my heart is glad and my tongue rejoices; my body also will dwell in hope,
Acts 2:26For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.
Romans 1:21Press and hold heart in any chapter and this study opens on the verse you are reading, with the lexicons, every occurrence and the commentaries beside it. The Bible is free to read.
Scripture quoted from the Berean Standard Bible, public domain. Strong's definitions are public domain. Counts come from The Pillar's own tagged text.