There is only one Sacrament of Holy Orders, but there are three levels.
The Ordination of Bishops
The first is that which Christ Himself bestowed upon His Apostles: the episcopate (meaning “over-seer”). A bishop is a priest who is ordained to the episcopate by another bishop (in practice, by several bishops). He stands in a direct, unbroken line from the Apostles, in what is known as “apostolic succession.” A diocesan bishop oversees a local church, a diocese. Almost the whole world is either in a diocese, or the mission territory of a diocese. Part of the responsibility of the papal nuncio, the pope’s direct representative in a given country, is to collect the names from bishops of his priests who might be considered worthy of examination to be raised to the office of bishop. Bishops report directly to the pope, the Bishop of Rome. Every five years, each diocesan bishop is required to make an “ad limina” (“to the threshold of”) visit to the tombs of Saints Peter and Paul, and to visit the Holy Father.
An archbishop is a bishop of an archdiocese, a diocese that has demographic or historical significance, and which has some limited authority over its suffragan dioceses. All of the dioceses in Pennsylvania are suffragan dioceses of the Archdiocese of Philadelphia. Those clergy called upon to “be given the red hat” and named to the college of cardinals are usually, but not always, archbishops.
Ordination as a bishop confers the grace to sanctify others, as well as the authority to teach the faithful and to bind their consciences. Because of the grave nature of this responsibility, all episcopal ordinations must be approved by the Pope.
The Ordination of Priests
The second level of the Sacrament of Holy Orders is the priesthood (the presbyterate, which means “elder”). All bishops are first priests. No bishop can minister to all of the faithful in his diocese, so priests act, in the words of the Catechism of the Catholic Church, as “co-workers of the bishops.” They exercise their powers lawfully only in communion with their bishop, and so they promise obedience to their bishop at the time of their ordination. The chief duties of the priesthood are the preaching of the Gospel and offering the Sacraments. The confection (consecration) of the Eucharist, and the forgiveness of sin in the Sacrament of Confession and the Sacrament of Anointing of the Sick, are reserved for priests.
A priest will begin his ministry as a “parochial vicar,” an assistant to a pastor (“parochial” means “parish,” and a “vicar” is someone who participates “vicariously” in the authority of another; a parochial vicar participates in the authority of the pastor). After several years of serving as a parochial vicar, there are many different jobs that priests can have in their priesthood. Most priests become “pastors,” that is, in charge of a parochial (parish) territory within the diocese. A priest may also have roles necessary for the administration of a diocese, in addition to or in place of serving as a pastor, or he may be assigned outside the diocese by his bishop (such as teaching in a seminary or university, or helping another diocese which has a shortage of priests).
In the Eastern Catholic Churches, married men are able to be ordained to the priesthood, but not the episcopacy. In the Western Church, the tradition is maintained that priests are celibate (unmarried). There are exceptions to this tradition, usually limited to Anglican priests who convert to Catholicism. Men who were invalidly married and were granted an annulment are valid candidates for holy orders, as are previously married men whose spouse has died. As in all cases, it is the prerogative of the bishop, following church law, his conscience, and prudence, whether to call someone to holy orders. No one has a right to ordination.
The Ordination of Deacons
The third level of the Sacrament of Holy Orders is the diaconate (which means “servant”). Deacons assist priests and bishops at the altar, in their pastoral care, and in the administration of the parish and diocese. Deacons are clergy who are also in the working and family world. Often they serve as pastoral associates: those who visit the elderly, the home-bound, the hospitalized, and the imprisoned. In the celebration of the Mass, the role of deacon is associated with proclaiming the gospel, with preaching, with offering the intercessions, with assisting the priest celebrant at the altar, and administering the chalice. At the celebration of the Easter Vigil Mass, the deacon is associated with the Paschal Candle, and proclaiming the Exsultet. Deacons are also ordinary ministers of the Rite of Baptism. In liturgical celebrations, deacons are often the thurifers, those who carry and use the incense.
All priests are first ordained to the diaconate, for a minimum of six months, and usually a year, before their ordination to the priesthood. This period is called his “transitional diaconate.” It is at his ordination as deacon that a man makes his promises to the bishop of obedience, to pray the divine office for and with the church, and, where applicable, to celibacy.
In the Eastern Churches, both Catholic and Orthodox, the permanent diaconate has been a constant feature. In the West, the permanent diaconate was suppressed for many centuries, and restored by the Second Vatican Council.
Married men may be ordained as permanent deacons. But once a man has received the sacrament of holy orders, may not receive the sacrament of holy matrimony. If a married man is ordained, and his spouse dies, he remains celibate.
Eligibility for the Sacrament
The Sacrament of Holy Orders can be validly conferred only on baptized men, following the example set by Christ and His Apostles, who chose only men as their successors and collaborators. A man cannot demand ordination; the Church has the authority to determine eligibility for the sacrament.
The Form of the Sacrament
As the Catechism of the Catholic Church notes:
The essential rite of the sacrament of Holy Orders for all three degrees consists in the bishop’s imposition of hands on the head of the ordained and in the bishop’s specific consecratory prayer asking God for the outpouring of the Holy Spirit and his gifts proper to the ministry to which the candidate is being ordained.
Other elements of the sacrament, such as holding it in the cathedral (the bishop’s own church); holding it during Mass; and celebrating it on a Sunday are traditional but not essential.
The Minister of the Sacrament
Because of his role as a successor to the Apostles, the bishop is the proper minister of the sacrament. The grace of sanctifying others that he receives at his own ordination allows him to ordain others.
The Effects of the Sacrament
The Sacrament of Holy Orders, like the Sacrament of Baptism and the Sacrament of Confirmation, can only be received once, for each level of ordination. Once a man has been ordained, he is spiritually (ontologically) changed, which is the origin of the saying, “Once a priest, always a priest.” He can be dispensed of his rights and obligations as a priest (or even forbidden to act as a priest); but he remains a priest forever.
Each level of ordination confers special graces, from the ability to preach, granted to deacons; to the ability to act in the person of Christ to offer the Mass, granted to priests; to a special grace of strength, granted to bishops, which allows him to teach and lead his flock, even to the point of dying as Christ did.