In this verse the Lord is saying that He will give us a heart that is united with His, and place within us the Holy Spirit, who will work on our behalf. The Lord will transplant our unrepentant, unyielding, hard as flint heart, and instead replace it with one that is undivided for Him. And the result will be us changed…a likeness of Jesus, His words not written on tablets of stone, but on tablets of our hearts.