Question: "How does the Orthodox Church views the nature of Holy Orders when compared to the view of the Roman Catholic Church. The Roman church claims that its priests are "Alter Christus," -- another Christ -- who undergo a fundamental change in being at their ordination, and who will be priests even in heaven or hell ("once a priest always a priest"). Does the Orthodox Church accept this formulation? Perhaps you could also express the Orthodox view of the Protestant notion of the "Priesthood of all believers.""
We of course believe that, not only priests, but all Christians, are called to be like Christ. We also believe that in certain respects and at certain times in the Liturgy a priest or bishop represent Christ in a symbolic sense. We do not believe that ordination leaves an “indelible mark on the soul” and that therefore once a person is ordained a priest or bishop, he is therefore “forever a priest, after the order of Melchizedek.” St. Basil’s 3rd and 32nd canon make clear that if a person is justly deposed, no sacrament that they perform would be valid.
In commenting on Canon 28 of the Holy Apostles, St. Nicodemus of the Holy Mountain compares someone who is unjustly deposed with an artist whose tools have been taken away from him. Once the unjust deposition is annulled, he is given back his tools, and is able to paint as before. But a person who is justly deposed is like an artist whose hands are crippled, and even if he takes up his tools again, he is unable to again do with them what he was able to do before.
As for the Protestant view of the "Priesthood of all believers," we would agree with them up to a point. St. Peter indeed says that "you also, as living stones, are being built up a spiritual house, a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ…. you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light" (1 Peter 2:5, 9). You also find the same idea expressed three times in the book of Revelation (Revelation 1:6; 5:10; 20:6). But you also find the same idea in the Old Testament. For example in the Law of Moses it says "And you shall be to Me a kingdom of priests and a holy nation." These are the words which you shall speak to the children of Israel" (Exodus 19:6).
However, in the Old Testament, even though they were a kingdom of priests, they still had a distinct priesthood. And there is a very interesting incident found in Numbers chapter 16, in which some people began to assert that there should not be such a distinction. In fact, the basic argument of Korah, Dathan and Abiram is not much different than what you hear from many Protestants:
"They gathered together against Moses and Aaron, and said to them, "You take too much upon yourselves, for all the congregation is holy, every one of them, and the Lord is among them. Why then do you exalt yourselves above the assembly of the Lord?"" (Numbers 16:3).
If you read the rest of that chapter, you will see that this attempt to democratize the Liturgical Priesthood of the Old Testament did not end well for them.
Deacons, priests, and bishops have a special grace that is bestowed upon them by the laying on of hands (ordination), and so they have a distinct role in leading the people in worship, and performing the sacraments of the Church. They also have special canonical requirements that not all Orthodox Christians are held to. For example, a blind or deaf person cannot be ordained. They also should have good character, and can only have been married once. And if a man who has married a women who has been married before, even if she is a widow, he cannot be ordained. This does not mean that there is any sin in marrying a widow, but it does mean that clergy have to meet certain standards of ritual purity to be ordained... and so must his wife, if he has one. But clergy function in these roles only because they have the blessing of the Church to do so. If that blessing is taken away, they cannot continue to function in those roles. Also, every Orthodox Christian can pray, and do all the services of the Church without a priest -- short of the sacraments and liturgical blessings specific to the clergy. For example, a parent can and should bless their children by making the sign of the cross over them. If an Orthodox layman is unable to attend a Church, they can do a Vigil as a reader service, and do Typika in the place of the Liturgy. An Orthodox Christian can even baptize someone in the case of an emergency. So we are all a kingdom of priests, but God has established a distinct priesthood to perform a particular role in the life of the Church.