Thomas Aquinas, Summa Theologiae

Objection 1: It seems that this sacrament ought not to be made of unleavened bread. because in this sacrament we ought to imitate Christ's institution. But Christ appears to have instituted this sacrament in fermented bread, because, as we have read in Ex. 12, the Jews, according to the Law, began to use unleavened bread on the day of the Passover which is celebrated on the fourteenth day of the moon; and Christ instituted this sacrament at the supper which He celebrated "before the festival day of the Pasch" (Jn. 13:1,4). Therefore we ought likewise to celebrate this sacrament with fermented bread.

Objection 2: Further, legal observances ought not to be continued in the time of grace. But the use of unleavened bread was a ceremony of the Law, as is clear from Ex. 12. Therefore we ought not to use unfermented bread in this sacrament of grace.

Objection 3: Further, as stated above (Question 65, Article 1; Question 73, Article 3), the Eucharist is the sacrament of charity just as Baptism is the sacrament of faith. But the fervor of charity is signified by fermented bread, as is declared by the gloss on Mt. 13:33: "The kingdom of heaven is like unto leaven," etc. Therefore this sacrament ought to be made of leavened bread.

Objection 4: Further, leavened or unleavened are mere accidents of bread, which do not vary the species. But in the matter for the sacrament of Baptism no difference is observed regarding the variation of the accidents, as to whether it be salt or fresh, warm or cold water. Therefore neither ought any distinction to be observed, as to whether the bread be unleavened or leavened.

On the contrary, According to the Decretals (Extra, De Celebr. Miss.), a priest is punished "for presuming to celebrate, using fermented bread and a wooden cup."

I answer that, Two things may be considered touching the matter of this sacrament namely, what is necessary, and what is suitable. It is necessary that the bread be wheaten, without which the sacrament is not valid, as stated above (Article 3). It is not, however, necessary for the sacrament that the bread be unleavened or leavened, since it can be celebrated in either.

But it is suitable that every priest observe the rite of his Church in the celebration of the sacrament. Now in this matter there are various customs of the Churches: for, Gregory says: "The Roman Church offers unleavened bread, because our Lord took flesh without union of sexes: but the Greek Churches offer leavened bread, because the Word of the Father was clothed with flesh; as leaven is mixed with the flour." Hence, as a priest sins by celebrating with fermented bread in the Latin Church, so a Greek priest celebrating with unfermented bread in a church of the Greeks would also sin, as perverting the rite of his Church. Nevertheless the custom of celebrating with unleavened bread is more reasonable. First, on account of Christ's institution: for He instituted this sacrament "on the first day of the Azymes" (Mt. 26:17; Mk. 14:12; Lk. 22:7), on which day there ought to be nothing fermented in the houses of the Jews, as is stated in Ex. 12:15,19. Secondly, because bread is properly the sacrament of Christ's body, which was conceived without corruption, rather than of His Godhead, as will be seen later (Question 76, Article 1, ad 1). Thirdly, because this is more in keeping with the sincerity of the faithful, which is required in the use of this sacrament, according to 1 Cor. 5:7: "Christ our Pasch is sacrificed: therefore let us feast . . . with the unleavened bread of sincerity and truth."

However, this custom of the Greeks is not unreasonable both on account of its signification, to which Gregory refers, and in detestation of the heresy of the Nazarenes, who mixed up legal observances with the Gospel.

Reply to Objection 1: As we read in Ex. 12, the paschal solemnity began on the evening of the fourteenth day of the moon. So, then, after immolating the Paschal Lamb, Christ instituted this sacrament: hence this day is said by John to precede the day of the Pasch, while the other three Evangelists call it "the first day of the Azymes," when fermented bread was not found in the houses of the Jews, as stated above. Fuller mention was made of this in the treatise on our Lord's Passion (Question 46, Article 9, ad 1).

Reply to Objection 2: Those who celebrate the sacrament with unleavened bread do not intend to follow the ceremonial of the Law, but to conform to Christ's institution; so they are not Judaizing; otherwise those celebrating in fermented bread would be Judaizing, because the Jews offered up fermented bread for the first-fruits.

Reply to Objection 3: Leaven denotes charity on account of one single effect, because it makes the bread more savory and larger; but it also signifies corruption from its very nature.

Reply to Objection 4: Since whatever is fermented partakes of corruption, this sacrament may not be made from corrupt bread, as stated above (Article 3, ad 4); consequently, there is a wider difference between unleavened and leavened bread than between warm and cold baptismal water: because there might be such corruption of fermented bread that it could not be validly used for the sacrament.

Articulus 4

Argumentum 1

Ad quartum sic proceditur. Videtur quod hoc sacramentum non debeat confici ex pane azymo. Debemus enim in hoc sacramento imitari institutionem christi. Sed christus videtur hoc sacramentum instituisse in pane fermentato, quia, sicut legitur Exod. XII, Iudaei secundum legem incipiebant uti azymis in die Paschae, quod celebratur quartadecima luna; christus autem instituit hoc sacramentum in cena, quam celebravit ante diem Paschae, ut habetur Ioan. XIII.

Ergo et nos debemus hoc sacramentum celebrare in pane fermentato.

Argumentum 2

Praeterea, legalia non sunt observanda tempore gratiae. Sed uti azymis fuit quaedam legalis caeremonia, ut patet Exod. XII.

Ergo in hoc sacramento gratiae non debemus azymis uti.

Argumentum 3

Praeterea, sicut supra dictum est, eucharistia est sacramentum caritatis, sicut baptismus fidei. Sed fervor caritatis significatur per fermentum, ut patet in Glossa, super illud Matth. XIII, simile est regnum caelorum fermento etc.. Ergo hoc sacramentum debet confici de pane fermentato.

Argumentum 4

Praeterea, azymum et fermentatum sunt accidentia panis, non variantia eius speciem. Sed in materia baptismi nulla discretio adhibetur circa differentiam accidentium aquae, puta si sit salsa vel dulcis, calida vel frigida.

Ergo in hoc sacramento aliqua discretio adhiberi non debet utrum panis sit azymus vel fermentatus.

Sed Contra

Sed contra est quod extra, de celebrat. Missar., cap. Litteras, punitur sacerdos qui in pane fermentato et scypho ligneo Missarum solemnia celebrare praesumpsit.

Corpus

Respondeo dicendum quod circa materiam huius sacramenti duo possunt considerari, scilicet quid sit necessarium, et quid conveniens. Necessarium quidem est ut sit panis triticeus, sicut dictum est, sine quo non perficitur sacramentum. Non est autem de necessitate sacramenti quod sit azymus vel fermentatus, quia in utroque confici potest. Conveniens autem est ut unusquisque servet ritum suae ecclesiae in celebratione sacramenti. Super hoc autem sunt diversae ecclesiarum consuetudines.

Dicit enim beatus Gregorius, in registro, Romana ecclesia offert azymos panes, propterea quod dominus sine ulla commixtione suscepit carnem. Sed ceterae ecclesiae offerunt fermentatum, pro eo quod verbum patris indutum est carne, sicut et fermentum miscetur farinae.

Unde, sicut peccat sacerdos in ecclesia Latinorum celebrans de pane fermentato, ita peccaret presbyter Graecus in ecclesia Graecorum celebrans de azymo pane, quasi pervertens ecclesiae suae ritum. Et tamen consuetudo de pane azymo celebrandi rationabilior est. Primo quidem, propter institutionem christi, qui hoc sacramentum instituit prima die azymorum, ut habetur Matth. XXVI, et Marc. XIV, et Luc. XXII, qua die nihil fermentatum in domibus Iudaeorum esse debebat, ut habetur Exod. XII.

Secundo, quia panis est proprie sacramentum corporis christi, quod sine corruptione conceptum est, magis quam divinitatis ipsius, ut infra patebit.

Tertio, quia hoc magis competit sinceritati fidelium, quae requiritur ad usum huius sacramenti, secundum illud I Cor. V, Pascha nostrum immolatus est christus, itaque epulemur in azymis sinceritatis et veritatis.

Habet tamen haec consuetudo Graecorum aliquam rationem, et propter significationem, quam tangit Gregorius; et in detestationem haeresis Nazaraeorum, qui legalia evangelio miscebant.

Ad 1

Ad primum ergo dicendum quod, sicut legitur Exod. XII, solemnitas paschalis incipiebat a vesperis quartaedecimae lunae.

Et tunc christus, post immolationem agni paschalis, hoc sacramentum instituit. Unde hic dies a ioanne dicitur praecedere sequentem diem Paschae, et a tribus aliis evangelistis dicitur prima dies azymorum, quando fermentatum in domibus Iudaeorum non inveniebatur, ut dictum est. Et de hoc supra notatum est plenius in tractatu dominicae passionis.

Ad 2

Ad secundum dicendum quod conficientes ex azymo non intendunt caeremonias legis servare, sed conformare se institutioni christi.

Et ideo non iudaizant. Alioquin et celebrantes in pane fermentato iudaizarent, quia Iudaei panes primitiarum fermentatos offerebant.

Ad 3

Ad tertium dicendum quod fermentum significat caritatem propter aliquem effectum, quia scilicet panem facit sapidiorem et maiorem. Sed corruptionem significat ex ipsa ratione suae speciei.

Ad 4

Ad quartum dicendum quod, quia fermentum habet aliquid corruptionis, et ex pane corrupto non potest confici hoc sacramentum, ut dictum est; ideo magis attenditur circa panem differentia azymi et fermentati quam circa aquam baptismi differentia calidi et frigidi. Posset enim tanta esse corruptio fermenti quod ex eo non posset fieri sacramentum.