In accordance with the watchword of the Year of Priesthood, announced by pope Benedict XVI: “The faithfulness of Christ – the faithfulness of a priest”, the article presents the actualization of the faithfulness of Christ in the Pallottine priestly ministry. The content of the article draws attention to Christ whose faithfulness we are trying to follow up to standards of the faithfulness of St. Vincent Pallotti, who – as the father of the Pallottine Family and founder of the Union of Catholic Apostolate that incorporates all the Church’s states into apostolate – is rightly called the great apostle of Rome. Considering the universalism of Pallotti’s idea of apostolate, both in the objective and subjective dimension, we restrict ourselves to presenting only chosen aspects of the thoroughly substantiated issue. We are doing it by firstly showing St. Vincent’s admiration for Christ’s ideal of priestly faithfulness, and then the ideal of fulfillment of Christ’s faithfulness in the Jerusalem upper room community. The culmination of the disquisition is the reflection on the mentioned above watchword of the Priesthood Year from the point of view of deepening of each priest’s identity, and particularly a Pallottine of the 21st century. It is strongly underlined that both the patron of the Priesthood Year, St. Jean-Baptiste-Marie Vianney – the parish priest of Ars, and St. Vincent Pallotti – the apostle of Rome, who lived at more or less the same time, can show to the priests of the 21st century how to cope with temptations threatening their saving mission in the community of God’s people, and also all over the world, which is still hostile, to a large extent, to the contents of God’s revelation, accomplished fully in the words and acts of Jesus, as the only begotten Son and the primal Apostle of the Preeternal Father. The point of the article states one sure thing: the most efficient means of a fight for man, for his great dignity of God’s child is nowadays – ultimately – authentic faithfulness to Christ, the only priest of the New and everlasting Covenant and to his Gospel preached for centuries in the Church and by the Church.