Lev is the Hebrew word for heart, and it means almost nothing that the English word "heart" means. In English, the heart is the seat of emotions: you follow your heart, you speak from the heart, your heart breaks, your heart loves. In Hebrew, the lev is the seat of will, decision, moral reasoning, and intention. It is the command center of the person. Not where you feel. Where you choose.

The KJV, ESV, NASB, and NIV all translate lev as "heart" without qualification, and the English reader immediately imports their own understanding: emotion, sentiment, feeling. This is not what the Hebrew is saying. When Proverbs 4:23 says "guard your lev, for from it flow the springs of life," it is not saying protect your feelings. It is saying protect your decision-making center, because every action in your life flows from the choices your lev has been making. When Pharaoh's lev is hardened in Exodus, it is not his feelings that stiffen. It is his will. His capacity to choose differently is what calcifies.

Jeremiah 31:33 says HaShem will write Torah on the lev. This is the New Covenant promise. If lev meant emotions, the promise would be that Torah would make you feel warm. It does not mean emotions. It means the decision center, the place where choices are formed before they become actions. HaShem is promising to rewrite your will, to restructure the place where you make every choice about how to live. When Yeshua says to love HaShem with all your lev, He is not asking for your sentiments. He is demanding your will. Every translation that gives you "heart" without explaining this is handing you an English word and letting you fill it with the wrong meaning.