He rendered perfect obedience because he knew your salvation depended on it. His perfect obedience provided for your atonement. Christ's throne of grace provides our confidence. You find mercy and grace to help in time of need. In times of failure, I need something more than the forgiveness that mercy provides.
Grace provides help.
Grace goes beyond not getting what we deserve. Grace enables us to discover God's power in times of temptation. When Paul struggled with his thorn in the flesh, God told him that divine grace was sufficient. Grace was sufficient to atone for his weakness and it also gave him strength as he struggled with his weakness. Grace empowered him to live above the condemnation of his weakness.