Catholic priesthood is facing many challenges from the point of view of modern culture, technological progress, and progressive secularism and fast changing socio - economic and political inequalities. Priests are very busy with their own activities. They have no time to spend for the people of God. Some think that there is no sense in talking about priesthood in a secularized world. Others feel that, by insisting on priesthood, the Church has brought about an unforgivable return to the ritualistic aspect of the Old Testament and so has rejected the authentic message of the gospel. Nowadays the relation between priests and the life of the people is decreasing. Many are criticizing our priesthood because of the lack of the faithfulness of some priests to their life. Here the question and relevance of this topic arises. Who is the real priest? The priest is expected to be another Christ to the people by his form of imitation of Him, by his penitential spirit and by his unity with poor and suffering. This dissertation is to analyze and to understand the priesthood introduced in the New Testament especially in the Letter to the Hebrews. In 2009 Pope Benedict wrote a letter to the priests related with year of priest. It provides a deeper understanding of the spiritual - theological understanding of the priesthood and its pastoral mission. The highlight is the servant model of priesthood given by Jesus with the intertwined dimensions of steward and shepherds models that make Catholic priesthood integral, effective and prophetically fruitful solution to the human miseries. Priests are the images of Christ. They have to live according to the life of Jesus. It is only in the Letter to the Hebrews we get a clear evidence for priesthood of Jesus from New Testament. The author is introducing Jesus as the fulfillment of the Old Testament priesthood. There we can see an evolution from the priesthood of Levi to the priesthood of Jesus. This evolution should happen in a seminarian life after a long year of formation.