Priesthood: What is a Priest
Every person is called to be a disciple of Jesus Christ. At our baptism, we are baptized into the common priesthood of all the faithful as we are called to our universal vocation to holiness. How we will live out that holiness will be different for each person. Some are called to live holiness as single persons, some within the vocation to the married life, some as religious brothers or sisters, and God calls some men to the ministerial priesthood.
Through the Sacrament of Baptism, the man shares in the priesthood of all the faithful; through the Sacrament of Holy Orders, the priest is configured to Christ, the Eternal High Priest. The Catechism of the Catholic Church describes the common and ministerial priesthood as “two participations in the one priesthood of Christ” and says:
The ministerial or hierarchical priesthood of bishops and priests, and the common priesthood of all the faithful participate, "each in its own proper way, in the one priesthood of Christ." While being "ordered one to another," they differ essentially. In what sense? While the common priesthood of the faithful is exercised by the unfolding of baptismal grace --a life of faith, hope, and charity, a life according to the Spirit--, the ministerial priesthood is at the service of the common priesthood. It is directed at the unfolding of the baptismal grace of all Christians. The ministerial priesthood is a means by which Christ unceasingly builds up and leads his Church. For this reason it is transmitted by its own sacrament, the sacrament of Holy Orders. (CCC n. 1547)
Through the grace of the Sacrament of Holy Orders, the priest is an alter Christus, another Christ, in the world. He is uniquely configured to Christ the High Priest and shares in the threefold mission to sanctify, to teach, and to govern. In the pattern of Jesus Christ, the priest ministers as one who “did not come to be served but to serve and to give his life as a ransom for many” (Mk 10:45). The priest offers his life in service to God and to His Body, the Church.
“The ministerial priesthood has the task not only of representing Christ - Head of the Church - before the assembly of the faithful, but also of acting in the name of the whole Church when presenting to God the prayer of the Church, and above all when offering the Eucharistic sacrifice.” (CCC n. 1552)