Summary: The grace of God is His gift to all who have fallen short, and it comes through the passion of Christ.
Did the scribes and Pharisees, the purveyors of the Law of Moses, actually realize what they were doing? It seems like the early Church believed that these super-Jews had all the proof they needed that Jesus is the Christ, but rejected Him anyway. Teaching with authority, miracles of healing, miracles of nature–none of these gifts of Christ stirred them to faith. Especially after Jesus’s death and resurrection, they refused to believe, and their spiritual heirs do so to this day. We should pray frequently for them to open their eyes and see and hear the truth of the Gospel of Jesus.
St. Paul tells us that the grace of God is His gift to all who have sinned and fallen short of God’s glory. That grace comes through the blood of Jesus Christ, the one who gives Himself in the Eucharist. We who take communion together in this extension of the Eucharist consume His Body, Blood, soul and divinity. We receive this divine gift by faith. What proves God’s love is that He gave His Son in this way even when we were jerks–especially when we have been evil and repent.
The popes pick up on this theme in paragraph 16 of the encyclical on faith:
"The clearest proof of the reliability of Christ’s love is to be found in his dying for our sake. If laying down one’s life for one’s friends is the greatest proof of love (cf. Jn 15:13), Jesus offered his own life for all, even for his enemies, to transform their hearts. This explains why the evangelists could see the hour of Christ’s crucifixion as the culmination of the gaze of faith; in that hour the depth and breadth of God’s love shone forth. It was then that Saint John offered his solemn testimony, as together with the Mother of Jesus he gazed upon the pierced one (cf. Jn 19:37): “He who saw this has borne witness, so that you also may believe. His testimony is true, and he knows that he tells the truth” (Jn 19:35). In Dostoevsky’s The Idiot, Prince Myskin sees a painting by Hans Holbein the Younger depicting Christ dead in the tomb and says: “Looking at that painting might cause one to lose his faith”.14 The painting is a gruesome portrayal of the destructive effects of death on Christ’s body.
"Yet it is precisely in contemplating Jesus’ death that faith grows stronger and receives a dazzling light; then it is revealed as faith in Christ’s steadfast love for us, a love capable of embracing death to bring us salvation. This love, which did not recoil before death in order to show its depth, is something I can believe in; Christ’s total self-gift overcomes every suspicion and enables me to entrust myself to him completely.
"Christ’s death discloses the utter reliability of God’s love above all in the light of his resurrection. As the risen one, Christ is the trustworthy witness, deserving of faith (cf. Rev 1:5; Heb 2:17), and a solid support for our faith. “If Christ has not been raised, your faith is futile”, says Saint Paul (1 Cor 15:17). Had the Father’s love not caused Jesus to rise from the dead, had it not been able to restore his body to life, then it would not be a completely reliable love, capable of illuminating also the gloom of death. When Saint Paul describes his new life in Christ, he speaks of “faith in the Son of God, who loved me and gave himself for me” (Gal 2:20). Clearly, this “faith in the Son of God” means Paul’s faith in Jesus, but it also presumes that Jesus himself is worthy of faith, based not only on his having loved us even unto death but also on his divine sonship."