The Angelic Doctor Against the Errors of the Greeks - Part Two - Chapter 39

Against the position of those who deny the Sacrament may be confected with unleavened bread.

But just as the aforesaid misguided persons sin against the unity of the mystical Body by denying the plenary power of the Roman Pontiff, so they sin against the purity of the sacrament of the Body of Christ, saying that the Body of Christ cannot be consecrated from unleavened bread. This, too, is disproved from texts of the Greek Doctors.

For Chrysostom commenting on the Gospel pericope, On the first day of the unleavened bread, says: “The first day he says is Thursday, on which observers of the Law began to celebrate the Passover, that is, to eat unleavened brewad, absolutely free of yeast. The Lord, therefore, sends his disciples on Thursday, which the Evangelist calls the first day of the unleavened bread, on which in the evening the Savior ate the Passover; in this deed, as in all he did from the beginning of his circumcision to the final day of his passover, he clearly showed that he was not opposed to divine laws.”  But it is obvious that he would have acted against the law if he had used leavened bread. Hence it is clear that in the institution of this sacrament Christ consecrated his body from unleavened bread.

It should be remarked,  however, that some  claim Christ anticipated the day of unleavened bread because his passion was at hand, and so used leavened bread. This they attempt to show on two grounds. First, because in John 13: 1, it is said that before the feast of the Passover Jesus celebrated with his disciples the supper in which he consecrated his body, as the Apostle teaches in 1 Cor. 11: 21. Whence it seems that Christ celebrated the Passover before the day of the unleavened bread, and so in the consecration of his body he used leavened bread. Further, they would confirm this by noting that according to John 18: 28, on the Friday on which Christ was crucified the Jews did not enter the praetorium of Pilate in order that they might not defile, but eat the Passover. But the Passsover is called the unleavened bread. They therefore conclude that the supper was celebrated before the unleavened bread.

To this, however, Chrysostom replies, commenting on that very text of John: That they might not be defiled, etc.: “What does this mean, but that they ate the Passover on another day and broke the law in order that they might fulfill the most wicked desire of their soul in the death of Christ; Christ, however, did not transgress Holy Thursday in paschal week, but on that day he ate the Passover.” 

But since this is not certain, it might be better to say that, as the Lord commands in Exodus 12:18-19, the feast of the unleavened bread was observed throughout seven days, of which the first day, that is, the fifteenth day of the month, was holier and more solemn than the others. But because among the Jews solemn feasts began to be celebrated on the preceding evening, the unleavened bread began to be eaten on the fourteenth day in the evening and was eaten during the seven following days. That is why it is said in the same chapter: In the first month, on the fourteenth day of the month in the evening, you shall eat the unleavened bread, until the twenty-first day of the month in the evening; for seven days leaven shall not be found in your houses. And on the same fourteenth day in the evening the paschal lamb was sacrificed.

Hence, the first day of the unleavened bread is called by the three Evangelists, Matthew 26: 17; Mark 14:12; and Luke 22:7, the fourteenth day of the month, because toward evening the unleavened bread was eaten and then the Passover, that is, the paschal lamb was sacrificed. And, according to John 13: 1, this was before the feast of the Passover, that is, before the fifteenth day of the month, because this was the most solemn day on which the Jews wished to eat the Passover, that is, the unleavened paschal bread as well as the paschal lamb. Thus, there being no disagreement among the Evangelists, it is plain that Christ consecrated his body from unleavened bread at the supper.

Clearly, also, this is more fitting for the purity of the mystical Body, that is, the Church, typified in this sacrament. Hence, Gregory Nazianzen says in his sermon on the feast of the Passover of the Lord: “Let us celebrate a feast to the Lord with jubilation, not in the leaven of malice and wickedness, but in the unleavened bread of sincerity and purity (1 Cor. 5:8).” 

We do not, however, mean by this that the sacrament may not be confected using leavened bread. For Pope Gregory says in his Register: “The Roman Church offers unleavened bread because the Word of the Father took flesh without any carnal conmingling; but other Churches offer leavened bread because the Word of the Father is clothed with flesh and is true God and true man. So, also, yeast is mixed with flour and this becomes the true body of our Lord Jesus Christ.”