You realize, don’t you, that if your arguments hold against LDS priesthood, they work equally well against the Catholic priesthood? After all, what do YOUR priests 'sacrifice?"
He’s talking about the Eucharist (I think that one or two other posters have brought up the issue of priests having to offer a sacrifice). The Eucharist/Mass is seen as a sacrifice in Catholicism and Orthodoxy. It is believed to be a re-presentation (not a re-do) of the once and for all sacrifice of Jesus Christ at Calvary. Basically, His sacrifice transcends time, and so the Catholic belief is that at Mass, we are transported back in time to Calvary, and Jesus’ sacrifice is presented. Here is what the Catechism of the Catholic Church says on this:
What is this Sacrament Called?
…
1330 The memorial of the Lord’s Passion and Resurrection.
The Holy Sacrifice, because it makes present the one sacrifice of Christ the Savior and includes the Church’s offering. The terms holy sacrifice of the Mass, “sacrifice of praise,” spiritual sacrifice, pure and holy sacrifice are also used,150 since it completes and surpasses all the sacrifices of the Old Covenant.
**
The sacrificial memorial of Christ and of his Body, the Church**
1362 The Eucharist is the memorial of Christ’s Passover, the making present and the sacramental offering of his unique sacrifice, in the liturgy of the Church which is his Body. In all the Eucharistic Prayers we find after the words of institution a prayer called the anamnesis or memorial.
1364 In the New Testament, the memorial takes on new meaning. When the Church celebrates the Eucharist, she commemorates Christ’s Passover, and it is made present the sacrifice Christ offered once for all on the cross remains ever present.185 "As often as the sacrifice of the Cross by which ‘Christ our Pasch has been sacrificed’ is celebrated on the altar, the work of our redemption is carried out."186
1365 Because it is the memorial of Christ’s Passover, the Eucharist is also a sacrifice. The sacrificial character of the Eucharist is manifested in the very words of institution: “This is my body which is given for you” and "This cup which is poured out for you is the New Covenant in my blood."187 In the Eucharist Christ gives us the very body which he gave up for us on the cross, the very blood which he “poured out for many for the forgiveness of sins.”
1366 The Eucharist is thus a sacrifice because it re-presents (makes present) the sacrifice of the cross, because it is its memorial and because it applies its fruit:
Code:
[Christ], our Lord and God, was once and for all to offer himself to God the Father by his death on the altar of the cross, to accomplish there an everlasting redemption. But because his priesthood was not to end with his death, at the Last Supper "on the night when he was betrayed," [he wanted] to leave to his beloved spouse the Church a visible sacrifice (as the nature of man demands) by which the bloody sacrifice which he was to accomplish once for all on the cross would be re-presented, its memory perpetuated until the end of the world, and its salutary power be applied to the forgiveness of the sins we daily commit.189
1367 The sacrifice of Christ and the sacrifice of the Eucharist are one single sacrifice: “The victim is one and the same: the same now offers through the ministry of priests, who then offered himself on the cross; only the manner of offering is different.” "And since in this divine sacrifice which is celebrated in the Mass, the same Christ who offered himself once in a bloody manner on the altar of the cross is contained and is offered in an unbloody manner. . . this sacrifice is truly propitiatory."190
scborromeo.org/ccc/p2s2c1a3.htm#V
So, when Catholics say that the priesthood is sacrificial, it means that they are offering the once and for all sacrifice of Jesus Christ, “re-presented”, on the altar.
Now, the Mass is also a sacrifice in another sense, which I think LDS would be more inclined to agree with:
1360 The Eucharist is a sacrifice of thanksgiving to the Father, a blessing by which the Church expresses her gratitude to God for all his benefits, for all that he has accomplished through creation, redemption, and sanctification. Eucharist means first of all “thanksgiving.”
1361 The Eucharist is also the sacrifice of praise by which the Church sings the glory of God in the name of all creation. This sacrifice of praise is possible only through Christ: he unites the faithful to his person, to his praise, and to his intercession, so that the sacrifice of praise to the Father is offered through Christ and with him, to be accepted in him.
However, the emphasis is on the Mass being a re-presentation of the once and for all sacrifice of Christ at Calvary.