Only Christ performs the "bloodless sacrifice" (i.e. the consecration of the Eucharist, that is the re-new of the sacrifice of the Cross).
The bishop/priest who presides the Liturgy/mass is simply a servant which gives his month and hands to Christ and to the community.
The bishop/priest is allowed to say the awful words of Christ, to call the Holy Spirit to came, only because he is granted this permission by Christ himself through the Church of Christ founded by the 12 Apostles
In the RCC there are many different ways to elect/choice who is to became bishop (the uses can change in any dioceses), but the important, as OrthodoxyUSA said, are the next two steps:
- the bishop/priest-elected shall be called by the Church. The service of the bishop/priest has a meaning only into the Church.
- the bishop/priest-elected shall be ordained by the laying of the hands by a bishop who was ordained in the same way, thus to built a chain back to the 11 Apostles and to Christ.
Obviously the Protestants have a very different idea of Church from Catholic or Orthodox, so they have a very different idea of this ministry too.
To be ordained bishop/priest does NOT mean to be more saint. The greater between the saints was not ordained bishop/priest: Mary (or think to other saints as Saint Francis of Assisis)
So dont confuse the sharing of the Melkiseded's priesthood (that is something that allow as to be saint) from the ordained priesthood of bishops/priests that is a ministry
Ministry to do Mass/Divine Liturgy appears to equate to office, right? The priestly office occupied by an ordained laity believer.
Perhaps this helps to explain the Melchizedek and "Aaronic-like" difference:
Catholic Encyclopedia:
"The simple fact that numerous
heretics, such as
Wyclif and
Luther, repudiated the Mass as
"idolatry", while retaining the
Sacrament of the
true Body and Blood of
Christ, proves that the
Sacrament of the Eucharist is something essentially different from the
Sacrifice of the Mass. In
truth, the Eucharist performs at once two functions: that of a sacrament and that of a sacrifice. Though the inseparableness of the two is most clearly seen in the fact that the consecrating sacrificial powers of the
priest coincide, and consequently that the sacrament is produced only in and through the Mass, the real difference between them is shown in that the sacrament is intended privately for the sanctification of the
soul, whereas the sacrifice serves primarily to glorify
God by
adoration, thanksgiving,
prayer, and expiation. The recipient of the one is
God, who receives the sacrifice of His
only-begotten Son; of the other, man, who receives the sacrament for his own good. Furthermore, the unbloody Sacrifice of the Eucharistic
Christ is in its nature a transient action, while the Sacrament of the Altar continues as something permanent after the sacrifice, and can even be preserved in
monstrance and
ciborium. Finally, this difference also deserves mention:
communion under one form only is the reception of the whole sacrament, whereas, without the use of the two forms of bread and wine (the symbolic separation of the Body and Blood), the mystical slaying of the victim, and therefore the Sacrifice of the Mass, does "