Holy Orders refers to those who are set apart for service in the Orthodox Christian Church. The origin of the word “order” is from the Latin ordo which designated an established civil body or corporation with a hierarchy, and ordinatio that means legal incorporation into an ordo. The word “holy” refers to the Church. Therefore, a holy order is a group with a hierarchy that is set apart for service in the Church.
It was the mission of the Apostles to go forth into all the world and preach the Gospel, baptizing those who believed in the name of the Holy Trinity (Matthew 28:18-20). In the early church those who presided over congregations were referred to variously as episopos (bishop) or presbyteros (priest). These successors of the Apostles were ordained to their office by the laying of hands and, according to Orthodox theology, form a living, organic link with the Apostles, and through them with Jesus Christ himself. This link continues in unbroken succession to this day. Over time, the ministry of bishops (who hold the fullness of the priesthood) and presbyters or priests (who hold a portion of the priesthood as bestowed by their bishop) came to be distinguished. In Orthodox terminology, the terms priesthood and sacerdotal refer to the ministry of bishops and priests. All of the ordination ceremonies take place during the Divine Liturgy.
The Orthodox Christian Church considers Ordination to all the offices of the Holy Orders be a Sacred Mystery that may only be conferred by a bishop, and not by a priest. All of the other Mysteries may be performed by a priest. Certain archimandrites may be given permission to bestow minor orders, but only a bishop may ordain a priest, deacon or, normally together with at least two other bishops, another bishop.
The offices of the Holy Orders in the Orthodox Church are grouped into two classes of orders: