How does the Orthodox Church operate? What makes it what it is?
Simply put, the Orthodox Church is made up of all people baptised and chrismated (confirmed) in the Orthodox Faith, overseen by the work of bishops, priests, and deacons, and supported by the prayer and example of monks and nuns.
“The Orthodox Church is made up all people baptised and chrismated (confirmed) in the Orthodox Faith, overseen by the work of bishops, priests, and deacons, and supported by the prayer and example of monks and nuns.”
The fullness of the Church is manifest when all the faithful, monastics, and clergy, are gathered around their bishop in the celebration of the Holy Eucharist in the Divine Liturgy. But where do these bishops come from? Who are the priests? What is a monastic? How does one become a member of 'the faithful'?
A Divine Structure
Bishops are the successors of the original apostles. This means that they have been ordained (appointed and prayed over) by other bishops, all of whom stand in the same tradition as their predecessors - that is, they hold exactly the same doctrines and practices as all those who came before them, extending all the way back to the original followers of Jesus Christ Himself.
Just as the original apostles first ordained deacons (Acts 6) to assist them in their service, so did their successors continue, even as they began to ordain 'presbyters' (or priests) to stand in for them in the local churches. Bishops could not be everywhere at once, so you might say that they ordained deacons to be their 'feet' and priests to be their 'hands' to carry on their work in the places they could not attend in person.
For this reason, an Orthodox priest today can do nothing in the Church without his bishop's explicit authority. This is signified by the 'antimension' - a cloth bearing an icon and the bishop's signature - that rests on the local altar where the priest is appointed to serve. When the local community gathers around that altar, it is in fact gathered around the delegated presence of the bishop, and the Church is so constituted.