I will run in the way of your commandments when you enlarge my heart! —Psalm 119:32
When God enlarges our heart, we get a NEW heart. John Piper helps us understand:
But forgiveness and cleansing is not enough. I need to be new. I need to be transformed. I need life. I need a new way of seeing and thinking and valuing. That’s why Ezekiel speaks of a new heart and a new spirit in(Ez. 36) verse 26 and 27: “I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.”
Here’s the way I understand those verses: To be sure, the heart of stone means the dead heart that was unfeeling and unresponsive to spiritual reality—the heart you had before the new birth could feel. It could respond with passion and desire to lots of things. But it was a stone toward the spiritual truth and beauty of Jesus Christ and the glory of God and the path of holiness. That is what has to change if we are to see the kingdom of God. So in the new birth, God takes out the heart of stone and puts in a heart of flesh. The word flesh doesn’t mean “merely human” like it does in John 3:6. It means soft and living and responsive and feeling, instead of being a lifeless stone. In the new birth, our dead, stony boredom with Christ is replaced by a heart that feels (spiritually senses) the worth of Jesus.
Then when Ezekiel says in verses 26 and 27, “a new spirit I will put within you. . . . And I will put my Spirit within you, and cause you to walk in my statutes,” I think he means that in the new birth, God puts a living, supernatural, spiritual life in our heart, and that new life—that new spirit—is the working of the Holy Spirit himself giving shape and character to our new heart.