Objection 10: Further, just as, in this sacrament, Christ's body is set before us as food, so is His blood, as drink. But in receiving Christ's body no other bodily food is added in the celebration of the mass. Therefore, it is out of place for the priest, after taking Christ's blood, to receive other wine which is not consecrated.
Objection 11: Further, the truth ought to be conformable with the figure. But regarding the Paschal Lamb, which was a figure of this sacrament, it was commanded that nothing of it should "remain until the morning." It is improper therefore for consecrated hosts to be reserved, and not consumed at once.
Objection 12: Further, the priest addresses in the plural number those who are hearing mass, when he says, "The Lord be with you": and, "Let us return thanks." But it is out of keeping to address one individual in the plural number, especially an inferior. Consequently it seems unfitting for a priest to say mass with only a single server present. Therefore in the celebration of this sacrament it seems that some of the things done are out of place.
On the contrary, The custom of the Church stands for these things: and the Church cannot err, since she is taught by the Holy Ghost.
I answer that, As was said above (Q. 60, A. 6), there is a twofold manner of signification in the sacraments, by words, and by actions, in order that the signification may thus be more perfect. Now, in the celebration of this sacrament words are used to signify things pertaining to Christ's Passion, which is represented in this sacrament; or again, pertaining to Christ's mystical body, which is signified therein; and again, things pertaining to the use of this sacrament, which use ought to be devout and reverent. Consequently, in the celebration of this mystery some things are done in order to represent Christ's Passion, or the disposing of His mystical body, and some others are done which pertain to the devotion and reverence due to this sacrament.
Reply Obj. 1: The washing of the hands is done in the celebration of mass out of reverence for this sacrament; and this for two reasons: first, because we are not wont to handle precious objects except the hands be washed; hence it seems indecent for anyone to approach so great a sacrament with hands that are, even literally, unclean. Secondly, on account of its signification, because, as Dionysius says (Eccl. Hier. iii), the washing of the extremities of the limbs denotes cleansing from even the smallest sins, according to John 13:10: "He that is washed needeth not but to wash his feet." And such cleansing is required of him who approaches this sacrament; and this is denoted by the confession which is made before the "Introit" of the mass. Moreover, this was signified by the washing of the priests under the Old Law, as Dionysius says (Eccl. Hier. iii). However, the Church observes this ceremony, not because it was prescribed under the Old Law, but because it is becoming in itself, and therefore instituted by the Church. Hence it is not observed in the same way as it was then: because the washing of the feet is omitted, and the washing of the hands is observed; for this can be done more readily, and suffices for denoting perfect cleansing. For, since the hand is the "organ of organs" (De Anima iii), all works are attributed to the hands: hence it is said in Ps. 25:6: "I will wash my hands among the innocent."
Reply Obj. 2: We use incense, not as commanded by a ceremonial precept of the Law, but as prescribed by the Church; accordingly we do not use it in the same fashion as it was ordered under the Old Law. It has reference to two things: first, to the reverence due to this sacrament, i.e. in order by its good odor, to remove any disagreeable smell that may be about the place; secondly, it serves to show the effect of grace, wherewith Christ was filled as with a good odor, according to Gen. 27:27: "Behold, the odor of my son is like the odor of a ripe field"; and from Christ it spreads to the faithful by the work of His ministers, according to 2 Cor. 2:14: "He manifesteth the odor of his knowledge by us in every place"; and therefore when the altar which represents Christ, has been incensed on every side, then all are incensed in their proper order.
Reply Obj. 3: The priest, in celebrating the mass, makes use of the sign of the cross to signify Christ's Passion which was ended upon the cross. Now, Christ's Passion was accomplished in certain stages. First of all there was Christ's betrayal, which was the work of God, of Judas, and of the Jews; and this is signified by the triple sign of the cross at the words, "These gifts, these presents, these holy unspotted sacrifices."
Secondly, there was the selling of Christ. Now he was sold to the Priests, to the Scribes, and to the Pharisees: and to signify this the threefold sign of the cross is repeated, at the words, "blessed, enrolled, ratified." Or again, to signify the price for which He was sold, viz. thirty pence. And a double cross is added at the words—"that it may become to us the Body and the Blood," etc., to signify the person of Judas the seller, and of Christ Who was sold.
Thirdly, there was the foreshadowing of the Passion at the last supper. To denote this, in the third place, two crosses are made, one in consecrating the body, the other in consecrating the blood; each time while saying, "He blessed."