The Orders of Clergy
κλῆρος — kleros · KLEE-ros
In brief
Orthodox clergy come in three major orders: bishops, priests, and deacons. The pattern is visible in the New Testament and fully formed by the early second century, and every Orthodox service still runs on it. Each order has its own liturgical work — the bishop presides and ordains, the priest celebrates the mysteries in his parish, the deacon leads the people's prayer — and none of them replaces the priesthood that belongs to all the baptized.
Three orders, one ministry
From its earliest days the Church has been served by ordained ministers in three major orders: the bishop (Greek episkopos, "overseer"), the priest or presbyter (presbyteros, "elder"), and the deacon (diakonos, "servant"). St. Paul already greets "the bishops and deacons" at Philippi (Philippians 1:1) and gives Timothy the qualifications for both (1 Timothy 3). In the New Testament the titles "elder" and "overseer" sometimes name the same men (Titus 1:5-7); the threefold pattern stands out with full clarity a generation later, in the letters St. Ignatius of Antioch wrote on the road to his martyrdom around the year 107 — for him it is already simply what the Church looks like.
The theology of this ministry — why the Church is episcopal at all, and how apostolic-succession works — is treated under Holy Orders, and the service by which men enter it under ordination. This entry is about what you see in church: who does what, and why the Liturgy wants all three.
What each order does in worship
The bishop is the Church's chief celebrant. Every mystery in his diocese hangs from his ministry: he alone ordains priests and deacons; the chrism used at every chrismation is consecrated only by the heads of the Churches; and every parish Liturgy is served on an antimension — the altar cloth signed by the bishop — and commemorates him aloud by name. When he is present, the whole service reorganizes itself around him (see the-bishop-in-the-liturgy). When he is absent, he is still in a real sense the host: the priest serves as his delegate.
The priest is the bishop's presence in the parish: he celebrates the Divine Liturgy and the daily services, baptizes, hears confessions, anoints the sick, crowns marriages, preaches, and blesses. The deacon is the Liturgy's great servant: he leads the litanies, calls the people to attention, chants the Gospel, censes, and moves continually between altar and congregation. The orders observe a strict grammar of dependence: a deacon never serves without a priest, and a priest cannot ordain his own successor. The system contains no self-made men — every ministry is received from another's hands, in a chain the Church traces back to the apostles.
The ranks within each order — protodeacon and archdeacon, archpriest and archimandrite, archbishop, metropolitan, patriarch (see clergy-titles-and-forms-of-address) — are titles of honor and administration, not additional orders: the newest deacon and the most senior patriarch each stand in one of the same three orders. Below the major orders stand the minor orders of reader and subdeacon, and beside them the blessed service of altar-servers and singers.
Married and monastic; clergy and laity
Orthodox practice, fixed in canon law by the end of the seventh century, allows a man to marry before ordination to the diaconate or priesthood but not after, while bishops are drawn from the celibate — ordinarily monastic — clergy. So the married parish priest and the monk-bishop are both entirely normal Orthodox figures, and neither is a concession.
Finally, the clergy do not exhaust the Church's priesthood. All the baptized share in the royal priesthood, and the Liturgy is celebrated by the whole assembly, each order — bishop, priest, deacon, and people — doing its proper part. "Amen" is a liturgical office too, and it belongs to the laity.