The new covenant has two parts to it: "I will give you a new heart and put a new spirit in you; I will remove from you your heart of stone and give you a heart of flesh" (Ezek. 36:26). God removed your old heart when he circumcised your heart; he gives you a new heart when he joins you to the life of Christ. That's why Paul can say "count yourselves dead to sin" and "alive to God in Christ Jesus" (Rom. 6:11).
The story of the Incarnation is the story of a descent and resurrection . . . one has the picture of a diver, stripping off garment after garment, making himself naked, then flashing for a moment in the air, and then down through the green, and warm, and sunlit water into the pitch black, cold, freezing water, down into the mud and slime, then up again, his lungs almost bursting, back again to the green and warm and sunlit water, and then at last out into the sunshine, holding in his hand the dripping thing he went down to get. This thing is human nature. (C. S. Lewis, "The Grand Miracle")
The Resurrection affirms the promise Christ made. For it was life he offered to give us: "I have come that they may have life, and have it to the full" (John 10:10). We are saved by his life when we find that we are able to live the way we've always known we should live. We are free to be what he meant when he made us. You have a new life-the life of Christ. And you have a new heart. Do you know what this means? Your heart is good.