Isaac was born supernaturally—there’s no way a 90-year-old woman could give birth. The thought of that was laughable. It was a miracle birth that had to be the divine intervention of God. That’s what grace is. Grace is knowing that it is humanly impossible for me to be good enough for God, so instead God must intervene supernaturally at the cross to perform a miracle. Jesus became sin for me so that I may become the righteousness of God.