The Catholic Church celebrated the 43rd annual World Day of Vocations on Sunday. At the Vatican, Pope Benedict XVI marked the occasion by ordaining 15 new priests and stressing how they must be a witness of the Gospel both to believers and to a world that has not yet heard of it.

13 of those ordained yesterday now become priests within the Diocese of Rome, while the two others will serve in the Order of Discalced Carmelites.

During his homily, the Holy Father recalled the day’s Gospel reading, which speaks of the Christ the Good Shepherd, who gives his life for his flock.

This priestly spirit, Benedict stressed, is opposed to "careerism, the attempt to arrive 'high up,' to seek out a position through the Church, serve oneself and not serve others. This is the image of a man who, through the priesthood, seeks to become important and famous."

Yet, he was quick to add, "the only legitimate ascent towards the ministry of the shepherd is the cross. That is the door."

He went on to say that to be a priest is not "to desire to be someone important, ... but to live for others, for Christ, and through Him and with Him to live for the men and women He seeks, whom He wants to lead along the path of life.”

"We enter the priesthood through a Sacrament," the Holy Father said, "and this means through the total donation of self to Christ, so that He may use me as He wishes, so that I serve Him and follow His call even when this contrasts with my own desires for self-fulfillment and respect. To enter by the door, which is Christ, means knowing Him and loving Him ever more deeply, that our will may unite with His and our action become one with His action."

He went on, stressing the importance of celebrating the Eucharist daily--an act which, he said, “must become a school of life for us, one in which we learn to donate our lives."

Likewise, he highlighted the importance of "a practical and concrete knowledge of the people entrusted to us. ... The pastor cannot be content with remembering names and dates, his knowledge must also be a knowledge of the heart. This, however, is only fully possible if the Lord has opened our own hearts."

The Pope concluded his homily by emphasizing how priests "must concern themselves with everyone," especially "those who believe and live with the Church," but also with "bringing God's invitation to His banquet to those men and women who have still not heard of it."