St. Paul is undoubtedly the greatest missionary of all times. He did not know Jesus Christ personally, but after his dazzling call on the road to Damascus, he became the greatest disciple, pleading the cause of Gentile converts. He was the Apostle of the Gentiles. The Oratorio is divided into several parts, and opens with the stoning of the first martyr Stephen whom Saul, then proud supporter of the traditions of the fathers, persecutor of Christians, although present was not directly involved. The vision of a Christian who dies like Christ, forgiving his persecutors, touches him deeply, throwing a seed in his soul that will sprout up to ripen slowly in Paul's consciousness that Christians are the Risen Jesus.

Continuing his persecution on the road to Damascus, the Lord is revealed. A light from the sky envelops him and a voice says to him, "Saul, Saul, why do you persecute me? [... ] I am Jesus whom you are persecuting. Rise and enter the city, and you will be told what you must do." From that moment he comes Paul, the Apostle of the Gentiles. He retreats into the wilderness to meditate on the gift received , spending three years in the most absolute concentration, after which he begins to preach the Gospel message in the Mediterranean world at the time, stating that "he is no longer alive, but Christ living in him ". The discovery that Christ is alive in the Church as in Stephen's and other Christians urges him to give his life for him. With his words he spreads the Gospel among the nations. His writings, retraced in recent pictures of the Oratorio , introduce us into the mystery of Christ, ultimately until the death on the cross for the salvation of man, speaking to us of his love, "caritas ", which can do everything, which is the largest and the end of all the virtues . Paul, therefore conforms to his Lord, and then follows him to martyrdom, to identify with him. The Oratorio ends with a march that seems to mark the footsteps of the Apostle to his final union with Christ. In this march, which ends with the triumphant tone of a hymn of praise, we hear his words, "Who shall separate us from the love of Christ? Neither the persecution ... nor the sword ...nor death! ."