Article III: On the Institution of the Eucharist

S. Th. III, q. 73, a. 5.

209. The Eucharist was instituted at the Last Supper, as the three Evangelists report: Matt. XXVI, Mark XIV, and Luke XXII, and the Apostle, I Cor. XI, and as the Council of Trent defines, sess. 13, c. 1.

This was done most fittingly: a) Christ is contained in this sacrament, whence He had to leave Himself under the species of a sacrament when He was about to depart in His own species. - b) The Eucharist represents the Passion of Christ and succeeded the sacrifices of the Old Law, whence it had to be instituted when the Passion was imminent, by which the old sacrifices representative of it had to cease. - c) Those things which are shown last by friends departing are accustomed to be the greatest signs of love, and those things which are said last are more retained and more deeply impressed upon the soul; whence this most excellent gift, to be retained with the greatest affection, had to be instituted immediately before the death of Christ.

210. Concerning the day on which Christ had the supper, there is controversy. - The Latins have taught rather commonly that it was held on the day on which the Jews had to eat the Paschal lamb with unleavened bread, namely, on the evening of the fourteenth day of the month Nisan (Matt. XXVI, 17, 20; Mark XIV, 12, 17; Luke XXII, 7), and consequently they say that Christ consecrated in such bread, and that Christ suffered on the very day of the feast of Passover.

On the contrary, the Greeks and certain modern critics hold that Christ suffered on the very day preparatory to the feast of Passover, on the evening of which the Passover was to be eaten (John XIII, 1, 29; XVIII, 28; XIX, 14, 31, 42; I Cor. V, 7), and consequently they teach that on the preceding day, namely the thirteenth, the Eucharist was instituted and that Christ anticipated the celebration of Passover. They explain this in various ways, either by saying that that anticipation was made according to the custom of the Galileans; or by asserting that in this year of the death of Christ there was doubt concerning the new moon and therefore concerning the day of Passover; or perhaps that a common doubt existed concerning the dating, and that the Pharisees ate the Passover at the evening of feria five, i.e. at the beginning of feria six, according to which dating the Synoptics speak; on the other hand, that the Sadducees celebrated at the evening of feria six (which they themselves called the fourteenth of Nisan), or as the Sabbath was beginning, according to which manner John speaks.¹

¹ Concerning this, cf. Lagrange, S. Marc, p. 318 sq.; Voste, Studia Ioannea, VIII; again Lagrange in Rev. Bibl., 1930, p. 287.

Hence the Greeks conclude that Christ used leavened bread, which they also use; yet undeservedly, because from the evening of the thirteenth day, which is the beginning of the fourteenth day, the Jews had to remove all leavened bread from the house, and because the Paschal Lamb anticipated by Christ was not eaten except with unleavened bread.