Some Catholic apologists have used Heb 9:23 as "proof" that the Mass is a propitiatory sacrifice, as, they argue, Christ is presenting sacrifices (plural) in heaven:
Thus it was necessary for the sketches of the heavenly things to be purified with these rites, but the heavenly things themselves need better sacrifices than these. (NRSV)
As Catholic apologist, Robert Sungenis, wrote:
Since Hb 9:23-24 clearly teaches that some kind of blood sacrifice is occurring presently in heaven, and since such sacrifice would constitute the ongoing work of Christ's eternal priesthood, we are not surprised to see Hb 9:23's use of the plural word "sacrifices" in the phrase "with better sacrifices than these" in reference to Christ's present work. Since Hb 9:22 introduced "blood" into the text as that which forgives sins, then Hb 9:23 would simply mean: "but the heavenly things themselves with better blood sacrifices than these." St. Paul is comparing and contrasting the Old Covenant "blood sacrifices" with the New Covenant "blood sacrifices." (Robert A. Sungenis, Not by Bread Alone: The Biblical and Historical Evidence for the Eucharistic Sacrifice [2d ed.; Catholic Apologetics International Publishing Inc., 2009], 66-69 [pp.67-68 are part of a lengthy footnote])
There are a number of problems with this interpretation. Fundamentally, the biblical texts that speak of Christ’s offering always presents it as a once-for-all action, and not one that can be repeated, whether in an unbloody manner or not per Catholic dogma, including the Epistle to the Hebrews.
Koine Greek has a word that denotes “finality” (εφαπαξ). It is predicated upon the accomplished work of Christ in the Greek New Testament (emphasis added):
For in that he died, he did unto sin once (εφαπαξ); but in that he liveth, he liveth unto God. (Rom 6:10)
Who needeth not daily, as those high priests, to offer up sacrifice first for his own sins, and then for the people’s: for this he did once (εφαπαξ), when he offered up himself. (Heb 7:27)
Neither by the blood of goats and calves, but by his own blood he entered in once (εφαπαξ) into the holy place, having obtained eternal redemption. (Heb 9:12)
By the which will we are sanctified through the offering of the body of Jesus Christ once (εφαπαξ) for all. (Heb 10:10)
Furthermore, in the Eucharistic theology of the New Testament authors, there are many indications that they did not hold to the substantial presence of Jesus in the Eucharist or the concept the Eucharist itself was a propitiatory sacrifice. For instance, in 1 Cor 11:26, Paul admonishes the Corinthians that, “. . .as often as ye eat this bread, and drink this cup, ye do shew the Lord’s death till he come.” Firstly, notice that Paul refers to the bread, after consecration, as still being “bread,” not the literal body of Christ under the appearance of bread. Furthermore, the term the KJV renders as “shew” is the Greek verb καταγγελω which means, not “to show” as some may think, but “to proclaim.” Such is an oddity if Catholic dogma is correct, and that the Eucharist is where Christ is substantially present in its celebration and His sacrifice is being re-presented to God the Father. Instead, believers are commanded to proclaim, not re-present, Christ until the Parousia (the second/final coming).
Furthermore, the use of the plural sacrifices the author is simply using the plural number for the sake of antithesis, or contrast, between the plural Old Covenant sacrifices and the once-for-all (εφαπαξ) sacrifice of the New Covenant. As one commentary cogently noted:
κρείττοσιν θυσίαις παρὰ ταύτας: the language is elliptical: "But [it is] necessary for the heavenly things [to be purified] with better sacrifices than those [of the earthly sanctuary]." The thought moves imperceptibly from the inauguration ceremonies to the sacrifices which formed an essential part of them. The plural θυσίαι, applied to the new covenant, is generic (cf. νεχροις, v. 17) and imprecise. The author is still drawing parallels between the old order and the new; the time has not yet come for him to emphasize, as in v.26, the unique of Christ's self-offering. (Peter Ellingworth, The Epistle to the Hebrews: A Commentary on the Greek Text [New International Greek Testament Commentary; Grand Rapids, Mich.: Eerdmans, 1993] 478)
There is nothing in Heb 9:23 that supports the Catholic Mass as a propitiatory sacrifice.