The gospel is saying that, what man cannot do in order to be accepted with God, this God Himself has done for us in the person of Jesus Christ. To be acceptable to God we must present to God a life of perfect and unceasing obedience to his will. The gospel declares that Jesus has done this for us. For God to be righteous he must deal with our sin. This also he has done for us in Jesus. The holy law of God was lived out perfectly for us by Christ, and its penalty was paid perfectly for us by Christ. The living and dying of Christ for us, and this alone is the basis of our acceptance with God