The theme of the Epistle to the Hebrews is Christ as our High Priest. As such, the "priestly" verses are very numerous (for example, 2:17, 3:1, 4:14-16, 5:1-10, 6:20, 7:1-28, 8:1-6, 9:11-15, 24-28, 10:19-22). The teaching here acquires much more meaning within Catholic Eucharistic theology, whereas, in evangelical, non-sacramental Protestant interpretation, it is necessarily "spiritualized" away. For nearly all Protestants, Jesus Christ is a priest only insofar as He dies sacrificially as the "Lamb" and does away with the Old Testament notion of animal sacrifice. This is not false, but it is a partial truth. Generally speaking, for the Catholic, there is much more of a sense of the ever-present Sacrifice of Calvary, due to the nature of the Mass, rather than considering the Cross a past event alone.
In light of the repeated references in Hebrews to Melchizedek as the prototype of Christ's priesthood (5:6,10, 6:20, 7:1-3,17,20), it follows that this priesthood is perpetual (forever), not one time only. For no one would say, for example, that Christ is King (present tense) if in fact He were only King for a short while in the past. This (Catholic) interpretation is borne out by explicit evidence in Hebrews 7:24-25:
He holds his priesthood permanently, because he continues for ever. Consequently he is able for all time to save those who draw near to God through him, since he always lives to make intercession for them.
If Jesus perpetually intercedes for us, why should He not also permanently present Himself as Sacrifice to His Father? The connecting word, consequently, appears to affirm this scenario. The very notion, fundamental to all strains of Christian theology, that the Cross and the Blood are efficacious here and now for the redemption of sinners, presupposes a dimension of "presentness" to the Atonement.
Granting that premise, it only remains to deny that God could, would, or should truly and actually re-present this one Sacrifice in the Mass. God certainly can do this, since He is omnipotent. He wills to do this because Jesus commanded the observance of the Lord's Supper (Luke 22:19). Lastly, one can convincingly contend that He should do this in order to graphically "bring home" to Christians His Passion, Crucifixion, and Resurrection, and to impart grace in a real and profound way in Communion. The one propitiatory Atonement of Calvary is a past event, but the appropriation of its spiritual benefits to Christians is an ongoing process, in which the Mass plays a central role.
The Sacrifice of the Mass, like the Real Presence in the Eucharist, is an extension of the Incarnation. Accordingly, there is no rational a priori objection (under monotheistic premises) to the concept of God transcending time and space in order to present Himself to His disciples. Nor is there any denying that the Sacrifice of Calvary is always present to God the Father and to Jesus Christ, God the Son. How then, can anyone deny that God could make the Cross sacramentally present to us as well?
Hebrews 7:24: "He holds his priesthood permanently, because he continues forever" is not just a one-time priestly sacrifice of Himself that has no application to His priesthood beyond the time it occurred in history). Yes, we agree that Jesus sacrificed Himself once on the Cross (7:27). But that is a one-time act, in history. Why, then, does 7:26 continue to refer to Jesus as a "high priest" in the present tense, "exalted above the heavens"? It is this paradoxical interplay between the one act and the "present-ness" of Jesus' priesthood that suggests a timeless nature of the sacrifice: precisely what Catholics claim is occurring at the Mass: the one-time sacrifice is being made present to us, because Jesus is a priest "forever."
It makes little sense to me to keep referring to Jesus as a "priest" in the present tense when He is (according to most Protestants) no longer doing at all what a priest does (sacrifice). Jesus sacrificed Himself as the Lamb of God. That was His priestly act (this is stated explicitly in 7:27, so it cannot be doubted).
But if that was strictly a past tense and not perpetual, why keep calling Him a priest after He is glorified in heaven? It would seem much more sensible to refer to His one-time priestly act, rather than continuing to call Him something denoting a characteristic activity that He is no longer performing.
If He is actively saving men -- present and future tense -- (as is undoubtedly true), but is doing so as a priest then He is presently saving by the sacrifice of Himself (i.e., the priestly act) which is an act made eternally "now". Thus we are right to the heart of the Sacrifice of the Mass, which is the same concept. Jesus saves us as a priest. The sacrifice is of both an ongoing and salvific nature. This is the Mass!
Jesus' Sacrifice is not only present to us on earth, but also in heaven. An "altar" is mentioned as in heaven, in the book of Revelation many times (6:9, 8:3,5, 9:13, 11:1, 14:18, 16:7). Why is this, if altars and priesthood ceased with the one Sacrifice of Jesus? This is after Jesus' Resurrection and Ascension. Nor is it just Jesus at this altar in heaven. We are told that the "prayers of the saints" are being offered there (5:8-9, 8:3-4). Altars are also mentioned elsewhere in the New Testament.
The climactic scene of the glorious portrayal of worship and adoration in heaven occurs in Rev 5:1-7. Verse 6 describes "a Lamb standing as though it had been slain." Since the Lamb (Jesus, of course) is revealed as sitting in the midst of God's throne (5:6, 7:17, 22:1,3; cf. Matthew 19:28, 25:31, Hebrews 1:8), which is in front of the golden altar (8:3), then it appears that the presentation of Christ to the Father as a Sacrifice is an ongoing (from God's perspective, timeless) occurrence, precisely as in Catholic teaching. Thus the Mass is no more than what occurs in heaven, according to the clear revealed word of Scripture. When Hebrews speaks of a sacrifice made once (7:27), this is from a purely human, historical perspective (which Catholicism acknowledges in holding that the Mass is a "re-presentation" of the one sacrifice at Calvary). However, there is a transcendent aspect of the Sacrifice as well.
Jesus is referred to as the Lamb 28 times throughout Revelation (compared to four times in the rest of the New Testament: John 1:29,36, Acts 8:32, 1 Peter 1:19). Why, in Revelation (of all places), if the Crucifixion is a past event, and the Christian's emphasis ought to be on the resurrected, glorious, kingly Jesus, as is stressed in Protestantism (as evidenced by a widespread disdain for, crucifixes)? Obviously, the heavenly emphasis is on Jesus' Sacrifice, which is communicated by God to John as present and "now" (Revelation 5:6; cf. Hebrews 7:24). The very notion of "lamb" possesses inherent sacrificial and priestly connotations in the Bible.
If this aspect is of such paramount importance even in the afterlife, then certainly it should be just as real and significant to us. The Sacrifice of the Mass bridges all the gaps of space and time between our Crucified Savior on the Cross and ourselves. Therefore, nothing at all in the Mass is improper, implausible, or unscriptural.
The Book of Hebrews and the scenes in heaven in the Book of Revelation are suffused with a worldview and “atmosphere” which is very "Catholic.” The Mass, rightly understood, fulfills every aspect of the above passages, most particularly in the sense of Christ as the ultimate Priest for Whom the earthly priest "stands in," and in the timeless and transcendent character of the Sacrifice "made present" at Mass, but never deemed to be an addition to, or duplication of, the one bloody Sacrifice of our Lord at Calvary.
St. Paul in 1 Corinthians 10:14-22, in an explicitly eucharistic passage, uses language suggesting that he sees the eucharist as a sacrifice involving an altar (hence priesthood, hence the Sacrifice of the Mass): He mentions the "altar" of the Old Covenant in 10:18 and makes a direct analogy with the altar of the New Covenant in 10:21:
You cannot drink of the cup of the Lord and the cup of demons. You cannot partake of the table of the Lord and the table of demons.
Catholic theologian and exegete Fernand Prat, S.J., comments on 1 Corinthians 10:
Wishing to show to the Corinthians that participating in idolatrous banquets is forbidden, whatever intention one may bring to them, because it is a scandal, a danger, and a formal act of idolatry, the Apostle appeals to their consciences: ". . . Behold Israel according to the flesh. Are not they that eat of the sacrifices partakers of the altar?" And St. Paul, deducing a code of morality from this doctrine, concludes in these words: "The things which the heathens sacrifice, they sacrifice to devils and not to God. I would not that you should be made partakers with devils [then the above passage follows]." If the arguments of the Apostle are not fallacious, the eucharistic communion is for Christians what the eating of food sacrificed to idols was for the Gentiles and what the sacred repast was for the Jews. Now the sacred banquet has a religious significance: it constitutes an act of worship in that it is a
complement of the sacrifice and unites the faithful with the sacrificing priest, with the altar where the victim was immolated and with the victim itself.
(The Theology of St. Paul, translated from the 10th French edition by John L. Stoddard, Westminster, MD: The Newman Bookshop, 1952, vol. 2 of 2, 268)
Even non-sacramental Baptists and many other Protestants have not completely avoided the language of priestly sacrifice, since they still speak of the "Lord's table"and even an "altar call." What altar? That is the language of priesthood and sacrifice. So Protestants can't help retaining a remnant of New Testament eucharistic and sacrificial, priestly talk. Hebrews 13:10 states that "we have an altar." Again, why, if the old system of priesthood is gone and the only priesthood of the New Covenant is that of Christ at Calvary? This is the New Covenant.