Sacerdotalism

Sacerdotalism is the belief that propitiatory sacrifices for sin require the intervention of a priest. That is, it is the belief that a special, segregated order of men, called the priesthood, are the only ones who can commune directly with God or the gods. This system of priesthood is exemplified by the priests in the Old Testament.

The term sacerdotalism comes from the Latin sacerdos, priest, literally one who presents sacred offerings (from sacer, 'the sacred', and dare, 'to give'); offerer of sacrifices. The related Latin term sacerdotium refers to the earthly hierarchy (of priests, bishops, etc.) whose primary goal is the salvation of the soul.

According to the Roman Catholic documents of the Second Vatican Council, sacerdotalism is the teaching that "through the ministry of priests, the spiritual sacrifice of the faithful is made perfect in union with the sacrifice of Christ, the sole Mediator. Through the hands of the priests and in the name of the whole Church, the Lord's sacrifice is offered in the Eucharist in an unbloody and sacramental manner until He Himself returns." Thus, priests "exercise within the Church a function of the apostles. They are empowered to perform the ministry of the Word, by which men are formed into the People of God. They catch up and draw into the Eucharistic Sacrifice the spiritual sacrifice of the common priesthood of the faithful". As such, only validly ordained Catholic priests with an apostolic lineage are able to offer the sacrifice of the Mass.

St. Thomas Aquinas puts it this way: "Although Christ's passion and death are not to be repeated, yet the power of that Victim Jesus endures forever, is eternal, for, as it is written, (Hebrews 10:14), 'by one oblation He hath perfected for ever them that are sanctified.'" Then he notes that the priest participates in that one eternal "redemptive act" (ongoing offering) sacramentally. His thinking runs like this: Jesus is both human/temporal and God/eternal. His offering on the cross was both eternal and human. In virtue of Jesus and his actions being eternal, his act of giving/offering on the cross has no beginning and no end. (There is no beginning or end in the eternal.) It is an ongoing offering and advocacy in eternity or heaven. In virtue of being part of the body of Christ (through baptism) the people of God, through a designated minister (priest), participate in this ongoing offering, advocacy, or sacrifice of Jesus sacramentally.

...
Wikipedia