The Roman Catholic Church teaches that during the Mass, their celebration of the Eucharist constitutes a propitiatory sacrifice for sin:
Council of Trent - Session 22, Chapter 2 (1562 AD)
And inasmuch as, in this divine sacrifice which is performed in the mass, that same Christ is contained and immolated in a bloodless manner, who once offered Himself in a bloody manner on the altar of the cross; the holy synod teaches, that this sacrifice is truly propitiatory, and that by means thereof this is effected, that we obtain mercy, and find grace in convenient aid, if we draw nigh unto God, contrite and penitent, with a true heart and upright faith, with fear and reverence. For the Lord, appeased by the oblation thereof, and granting the grace and gift of penitence, forgives even heinous crimes and sins. For the victim is one and the same, the same now offering by the ministry of priests, who then offered Himself on the cross, the manner alone of offering being different.
The fruits indeed of which oblation, of that bloody one, to wit, are most plentifully received through this bloodless one; so far is this latter from derogating in any way from that former [oblation]. Wherefore, not only for the sins, punishments, satisfactions, and other necessities of the faithful who are alive, but also for those who are departed in Christ, and who are not as yet fully purified, is it rightly offered, agreeably to a tradition of the apostles.
Notice that above, the Catholic Church denies that the Eucharist is a distinct sacrifice from the one that Jesus Christ made on the cross. Rather, it is a re-presentation of that same sacrifice. It is through this re-presentation that "the fruits" of the Lord's sacrifice on the cross are dispensed. Therefore, it is "offered" for "the sins, punishments, satisfactions, and other necessities of the faithful".
The Catholic Church also teaches that when the words of consecration are spoken over the bread and wine by the priest, they become the actual body and blood of Jesus Christ:
Council of Trent - Session 13, Chapter 4 (1551 AD)
But because Christ, our Redeemer, declared that which He offered under the species of bread to be verily His own body, therefore has it ever been a firm belief in the Church of God, and this holy Synod doth now declare it anew, that, by the consecration of the bread and of the wine, a conversion takes place of the whole substance of the bread into the substance of the body of Christ our Lord, and of the whole substance of the wine into the substance of His blood. Which conversion is, by the holy Catholic Church, conveniently and properly called Transubstantiation.
In order for the above to make sense, a person must hold to a view of metaphysics wherein there exists something called "species" that can be distinguished from "substance". Somehow, the "substance" can be totally changed ("trans-substance-iation"), and yet, the "species" can remain exactly the same.
This is an outdated view of reality, propounded by Aristotle, who taught that things have a "substance", which is what something is in its deepest reality, and "accidents" (species), which are qualities that do not determine the substance's identity, such as color, taste, or size. This concept of reality is now known to be false, as things are comprised of atoms, and if those atoms change, so will the chemical properties and appearance of whatever was affected. There is no "essence" of bread and wine. Rather, they are non-living collections of molecules - carbohydrates, proteins, etc.
For more quotations to establish that the Mass, according to the Roman Catholic Church, can properly be called a "sacrifice" and "offering", along with other quotations regarding Transubstantiation, see Appendix I.
The most common proof texts utilized by Roman Catholics for the doctrine Transubstantiation are:
Therefore, each passage will be addressed below.
At the Last Supper, the Lord said the following when instituting the ordinance of the Lord's Supper (Luke 22:19):
Matthew 26:26-28
26 And as they were eating, Jesus took bread, and blessed it, and brake it, and gave it to the disciples, and said, Take, eat; this is my body.
27 And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it;
28 For this is my blood of the new testament, which is shed for many for the remission of sins.
To begin, the most straightforward way to take the above is figurative, as the bread and wine did not actually turn into human flesh or blood. The fact that the elements remained bread and wine, and were consumed afterwards, despite the Old Testament prohibition on consuming blood (Genesis 9:4, Leviticus 3:17, 7:26-27, 17:10-14, Deuteronomy 12:16, 12:23-25, 15:23), is an obvious indication that a hyper-literal interpretation needs to be rejected. The doctrine of Transubstantiation is an attempt to somehow reconcile a hyper-literal interpretation of the passage, when the passage itself refutes the idea that Jesus's actual body was offered and eaten at the Last Supper.
A second reason the passage is obviously symbolic is that it refers to events which had not happened yet. In the passages, the Lord says the blood being spoken of "is shed for many". However, obviously, this had not happened yet. It was to happen the next day, when He was crucified. No blood had been shed at this point. Therefore, Christ is using the bread and wine as prophetic symbols of His body being "broken", as the bread was, and His blood being shed, as the wine was poured.
If, on the other hand, Jesus Christ's blood had been shed, and offered to God "for the remission of sins", as the passages say, at the Last Supper, then it would mean that His crucifixion the next day was the second offering that He made. But Hebrews 10:10-14, which will be covered later in this article, makes it clear that Christ made one offering of one sacrifice to God, and it was the sacrifice made on the cross - not the Last Supper. This is also taught in 1 Peter 2:24, which says that Jesus bore our sins specifically on the cross, not at the Last Supper.
This view is further evidenced by the Lord specifically saying that the blood being referred to was the "blood of the New Testament". However, book of Hebrews explicitly says that the New Covenant did not begin until the death of Christ:
Hebrews 9:15-17
15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
16 For where a testament is, there must also of necessity be the death of the testator.
17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth.
Therefore, the most straightforward reading of the Last Supper passages, which places them in harmony with the rest of Scripture, is to understand that the Lord was prophesying of His death which was to take place the next day, and used the symbols of bread and wine to represent that, and not that an actual transmutation or offering took place.
In John chapter 6, in response to a challenge to produce a sign like the manna which fell during the Exodus, Jesus says:
John 6:30-36
30 They said therefore unto him, What sign shewest thou then, that we may see, and believe thee? what dost thou work?
31 Our fathers did eat manna in the desert; as it is written, He gave them bread from heaven to eat.
32 Then Jesus said unto them, Verily, verily, I say unto you, Moses gave you not that bread from heaven; but my Father giveth you the true bread from heaven.
33 For the bread of God is he which cometh down from heaven, and giveth life unto the world.
34 Then said they unto him, Lord, evermore give us this bread.
35 And Jesus said unto them, I am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
36 But I said unto you, That ye also have seen me, and believe not.
Notice that Jesus says that He is "The Bread of Life". Yet, the way that one can partake of that bread, according to the same verse, is by "coming" to Him, which is then defined as "believing" in Him (verse 35). And, those present are upbraided in verse 36 - not for failing to eat Transubstantiated bread - but for the fact that they "believe not".
The other relevant passage in the chapter is the following:
John 6:48-58
48 I am that bread of life.
49 Your fathers did eat manna in the wilderness, and are dead.
50 This is the bread which cometh down from heaven, that a man may eat thereof, and not die.
51 I am the living bread which came down from heaven: if any man eat of this bread, he shall live for ever: and the bread that I will give is my flesh, which I will give for the life of the world.
52 The Jews therefore strove among themselves, saying, How can this man give us his flesh to eat?
53 Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you.
54 Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day.
55 For my flesh is meat indeed, and my blood is drink indeed.
56 He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him.
57 As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me.
58 This is that bread which came down from heaven: not as your fathers did eat manna, and are dead: he that eateth of this bread shall live for ever.
The meaning of the above passage, in which Christ uses the language of "eating" and "drinking" His flesh and blood, can be understood by noting that the following 7 passages from this chapter all have the same consequence - Everlasting Life:
John 6:35, 40, 44, 47, 51, 54, 58
35 And Jesus said unto them, am the bread of life: he that cometh to me shall never hunger; and he that believeth on me shall never thirst.
40 And this is the will of him that sent me, that every one which seeth the Son, and believeth on him, may have everlasting life: and I will raise him up at the last day.
44 No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day.
47 Verily, verily, I say unto you, He that believeth on me hath everlasting life.
51 I am the living bread which came down from heaven: if any man eat of this bread, he shall live for ever: and the bread that I will give is my flesh, which I will give for the life of the world.
54 Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day.
58 This is that bread which came down from heaven: not as your fathers did eat manna, and are dead: he that eateth of this bread shall live for ever.
Above, "coming to" Christ, "believing" in Christ, and "eating" His flesh and "drinking His blood", all have the same result for the one who does so - Everlasting Life. The spiritual application, therefore, is belief, and the physical metaphor is eating and drinking. This metaphor is intended to show how we subsist and get life from Christ - by faith.
The Roman Catholic misinterpretation of what is spoken by the Lord in this chapter is echoed by the Jews present, who in verse 52, take what Christ is saying hyper-literally, remarking "How can this man give us his flesh to eat?".
This is part of a running theme in the Gospel of John where people take Jesus's spiritual lessons too literally. First, there Nicodemus thinking that being "born again" would requiring entering his mother's womb a second time (John 3:4). Then in chapter 4, there is the woman at the well thinking that the "Living Water" will ensure that she doesn't have to come to the well to draw again (John 4:15). Then here in John 6, some of those present mistakenly think that eating Jesus's flesh is literal (John 6:52). The Bible must be read in context. All three instances were spiritual metaphors for believing in Jesus, and finding Everlasting Life in Him by that faith.
A further warning against a hyper-literal interpretation of this passage would be that Jesus says that whoever eats of the bread being spoken of "shall never hunger" (John 6:35). Of course, those who eat the Roman Catholic Eucharist still physically hunger after doing so. So, the passage is indicating the spiritual nature of what is being said, in a way which disallows hyper-literalism. And, it is worth noting that since Roman Catholicism teaches that one can eat the "Bread of Life" spoken of in this chapter - the literal body of Jesus, allegedly - and still go to Hell, they do not take "never hunger" literally in any sense.
Finally, to point out an obvious contextual problem with the Catholic interpretation of this chapter - the Lord's Supper would not be instituted until many months after the events in John chapter 6, and so applying this passage to the Lord's Supper is not possible. Jesus Christ spoke in the present tense in the passage when mentioning "eating" His flesh and "drinking" His blood, meaning it was something that was possible to do while He was talking. This is consistent with understanding these terms to be symbolic of believing in Him, which could be done right there and then, rather than eating Transubstantiated bread which did not even exist yet. And again, the Lord upbraids people for their unbelief in the chapter (John 6:36, 6:64), not their failure to actually eat Him.
When discussing the misbehavior of some of those at the church in Corinth at the Lord's Supper, the Apostle Paul writes:
1 Corinthians 11:23-29
23 For I have received of the Lord that which also I delivered unto you, that the Lord Jesus the same night in which he was betrayed took bread:
24 And when he had given thanks, he brake it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me.
25 After the same manner also he took the cup, when he had supped, saying, this cup is the new testament in my blood: this do ye, as oft as ye drink it, in remembrance of me.
26 For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come.
27 Wherefore whosoever shall eat this bread, and drink this cup of the Lord, unworthily, shall be guilty of the body and blood of the Lord.
28 But let a man examine himself, and so let him eat of that bread, and drink of that cup.
29 For he that eateth and drinketh unworthily, eateth and drinketh damnation to himself, not discerning the Lord's body.
To begin, it should be noted that non-Catholics have no issue with this passage as it appears on its face, as they do not deny that the bread and wine used in the Lord's Supper represent His body and blood. Therefore, someone disrespecting the symbol is sinning in the same grievous way that someone disrespecting baptism disrespects Jesus's death and resurrection. Therefore, being "guilty of the body and blood of the Lord" refers to blaspheming God by dishonoring the symbols that He instituted to represent His atoning work of redemption.
Furthermore, in the previous chapter, a statement is made in relation to the Lord's Supper that can be used to demonstrate the symbolic nature of the language used elsewhere in Scripture to describe the Lord's Supper:
1 Corinthians 10:16-17
16 The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ?
17 For we being many are one bread, and one body: for we are all partakers of that one bread.
Above, the Apostle Paul says that believers are "one bread". Using the standards of Roman Catholic hermeneutics, one could use this passage to prove that believers are also eating the whole Church "under the species" of bread and wine at the Lord's Supper, because the Church is the Body of Christ (Ephesians 1:22-23, Colossians 1:18, 1:24), and, according to this passage, we are "one bread". Rather, a hyper-literal interpretation of this passage is just as illogical as the hyper-literal interpretation of the other proof texts discussed thus far.
The book of Hebrews is critical in discussions of the nature of the Mass, due to the fact that it is emphatic that Jesus Christ made one sacrifice for sin, and also made one offering of that sacrifice, in distinction from the repeated sacrifices and offerings that the priests performed under the Old Covenant:
Hebrews 9:25-28
25 Nor yet that he should offer himself often, as the high priest entereth into the holy place every year with blood of others;
26 For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself.
27 And as it is appointed unto men once to die, but after this the judgment:
28 So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation.
Hebrews 10:10-14, 18, 26
10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.
11 And every priest standeth daily ministering and offering oftentimes the same sacrifices, which can never take away sins:
12 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
13 From henceforth expecting till his enemies be made his footstool.
14 For by one offering he hath perfected for ever them that are sanctified.
18 Now where remission of these is, there is no more offering for sin.
26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
Notice, "Christ was once offered", and made "one sacrifice for sins for ever". "There is no more offering for sin", because "by one offering he hath perfected forever them that are sanctified". This is emphatic, and the message is clear that there was but one sacrifice, and critically - one single, perfect offering of that sacrifice, which perfects "forever" those who receive it.
These passages do not accommodate the Roman Catholic doctrine that the Mass is an unbloody, re-presentation of the "one offering" of Christ's "one sacrifice". In fact, such a doctrine would seem to be the definition of finding a nonsensical way to nullify a very clear passage of Scripture. If the single offering that Jesus made was perfect, it does not need to be re-presented. If it did, then it would not be perfect (viz., complete, sufficient). If one can partake of the Eucharist at the Mass, and still go to Hell, then how can that be the "same offering" of the "same sacrifice" of Christ on the cross, when the book of Hebrews says that after such an offering, "there is no more sacrifice for sin", as this offering "perfected for ever them that are sanctified"?
In fact, the language of "re-presenting" the "one offering" that is often used in discussions of this topic by Roman Catholics is fundamentally nonsensical. Whatever nuance can be drummed up between "offer" and "present" is certainly not a Biblical nuance. The Bible makes no such distinction. The words are synonyms, as if the cleansing blood of Christ is "offered", then it is "presented". The Mass is not a "re-presentation" of a "one offering", but rather, an attempt to "re-offer" an offering that God made very clear was only to be offered once.
The Lord's Supper is an ordinance given to the Church by the Lord, who instructed believers at the Last Supper to "do this in remembrance of me" (Luke 22:19: 1 Corinthians 11:24-25). Therefore, believers repeat this symbol of His atoning work to "show the Lord's death till He come" (1 Corinthians 11:26).
The Roman Catholic doctrines that the Communion elements of bread and wine actually turn into the body and blood of Jesus, and also constitute an ongoing "propitiatory sacrifice" for sin, are derogations of the work of Jesus Christ, and unbiblical.
Council of Trent - Session 13 (1551 AD)
Canon 1 - If any one shall deny, that, in the sacrament of the most holy Eucharist, are verily, really, and substantially contained the body and blood, together with the soul and divinity, of our Lord Jesus Christ, and consequently the whole Christ; but shall say that He is only therein as in a sign, or in figure, or virtue; let him be anathema.
Canon 2 - If any one shall say, that, in the sacred and holy sacrament of the Eucharist, the substance of the bread and wine remains conjointly with the body and blood of our Lord Jesus Christ, and shall deny that wonderful and singular conversion of the whole substance of the bread into the Body, and of the whole substance of the wine into the Blood, the species only of the bread and wine remaining, which conversion indeed the Catholic Church most aptly calls Transubstantiation; let him be anathema.
Council of Trent - Session 22 (1562 AD)
Canon 1 - If any one shall say, that in the mass a true and proper sacrifice is not offered to God; or, that to be offered is nothing else but that Christ is given unto us to eat; let him be anathema.
Canon 3 - If any one shall say, that the sacrifice of the mass is only a sacrifice of praise and of thanksgiving; or, that it is a bare commemoration of the sacrifice offered on the cross, but not a propitiatory sacrifice; or, that it avails him only who receiveth; and that it ought not to be offered for the living and the dead for sins, punishments, satisfactions, and other necessities; let him be anathema.
Council of Trent - Pope Pius IV's Bull on the Profession of Faith (1564 AD)
I embrace and receive all and everything which in the holy Synod of Trent has been defined and declared concerning original sin and justification. I profess likewise that in the Mass is offered to God a true, proper, and propitiatory sacrifice for the living and the dead, and that in the most holy sacrament of the Eucharist there is truly, really, and substantially the body and blood, together with the soul and divinity, of our Lord Jesus Christ, and that there takes place a conversion of the entire substance of the bread into the body, and of the entire substance of the wine into the blood, which conversion the Catholic Church calls transubstantiation.
Catechism of the Catholic Church 1323
1323 "At the Last Supper, on the night he was betrayed, our Savior instituted the Eucharistic sacrifice of his Body and Blood. This he did in order to perpetuate the sacrifice of the cross throughout the ages until he should come again, and so to entrust to his beloved Spouse, the Church, a memorial of his death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a Paschal banquet 'in which Christ is consumed, the mind is filled with grace, and a pledge of future glory is given to us.'"
Catechism of the Catholic Church 1364
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. "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."
Catechism of the Catholic Church 1366
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:
[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.
Catechism of the Catholic Church 1367
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." "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."
Catechism of the Catholic Church 1393
1393 Holy Communion separates us from sin. the body of Christ we receive in Holy Communion is "given up for us," and the blood we drink "shed for the many for the forgiveness of sins." For this reason the Eucharist cannot unite us to Christ without at the same time cleansing us from past sins and preserving us from future sins:
Catechism of the Catholic Church 1414
1414 As sacrifice, the Eucharist is also offered in reparation for the sins of the living and the dead and to obtain spiritual or temporal benefits from God.
Sometimes in debate, a Roman Catholic will raise an objection to the effect of:
Is this not like your concept of confession and fellowship forgiveness? Are not those sins forgiven as you confess them on the basis of that same "one offering" of the "one sacrifice" of Christ?
This is a fair question, so it is worth responding to. Here is the difference:
Firstly, we can point to something that was actually perfected, namely, our spirit, which was passed from death unto life when we believed (Ephesians 2:1). And, we can truly say that all of our sins are gone forever, judicially before God (Revelation 1:5, Romans 5:1, etc.), and in the New Man, which is sinless (2 Corinthians 5:17). We would emphasize the atonement spoken of in the passages in question in the book of Hebrews as that eternal forgiveness, in the sense of atonement, that is received upon justification, when all of our sins are judicially forgiven, and no longer the basis for our eternal condemnation before God, and we are imputed the righteousness of Jesus Christ. So, we can affirm, and personally apply, exactly what is said in the passages in Hebrews, unlike in Roman Catholicism, which lacks a perfected atonement in any sense for the individual believer at any point before they die, and endure Purgatory, if they are fortunate enough to be sent there instead of Hell, which they are still liable to go to regardless of how many times they have been to Mass or Confession, if they die with a Mortal Sin on their soul.
However, our temporal fellowship forgiveness, which is obtained via confession of sins, is about restoration of fellowship in-time for sins which have already been atoned for in the eternal sense. So when 1 John 1:9 talks about forgiveness, we view this as restoration of fellowship, not atonement. The atonement is already secured for those sins which are being confessed, only the temporal distancing of ourselves from God in our experience remains, much in the same way that although David's sin was forgiven, he still suffered consequences in time (feeling distant from God, temporal consequences), and we as believers, though already perfected, experience temporal chastisement and consequences for our sins (Hebrews 12:6). So, the word "forgiveness" in a passage like 1 John 1:9 is being used in that sense - restoration of fellowship and repairing a temporal relationship with a Personal Being, God - not judicial atonement.
Then of course, the form is very different - there are no priests, and no language of "immolation", "altar", "victim", "sacrifice", or "offering", as we believe the sacrifice and offering are already done, and we simply repair our fellowship in time, in light of that.