However, it was possible at the time of the Law, for the minds of the faithful, to be united by faith to Christ incarnate and crucified; so that they were justified by faith in Christ: of which faith the observance of these ceremonies was a sort of profession, inasmuch as they foreshadowed Christ. Hence in the Old Law certain sacrifices were offered up for sins, not as though the sacrifices themselves washed sins away, but because they were professions of faith which cleansed from sin. In fact, the Law itself implies this in the terms employed: for it is written (Lev. 4:26; 5:16) that in offering the sacrifice for sin "the priest shall pray for him . . . and it shall be forgiven him," as though the sin were forgiven, not in virtue of the sacrifices, but through the faith and devotion of those who offered them. It must be observed, however, that the very fact that the ceremonies of the Old Law washed away uncleanness of the body, was a figure of that expiation from sins which was effected by Christ.
It is therefore evident that under the state of the Old Law the ceremonies had no power of justification.
Reply Obj. 1: That sanctification of priests and their sons, and of their apparel or of anything else belonging to them, by sprinkling them with blood, had no other effect but to appoint them to the divine worship, and to remove impediments from them, "to the cleansing of the flesh," as the Apostle states (Heb. 9:13) in token of that sanctification whereby "Jesus" sanctified "the people by His own blood" (Heb. 13:12). Moreover, the expiation must be understood as referring to the removal of these bodily uncleannesses, not to the forgiveness of sin. Hence even the sanctuary which could not be the subject of sin is stated to be expiated.
Reply Obj. 2: The priests pleased God in the ceremonies by their obedience and devotion, and by their faith in the reality foreshadowed; not by reason of the things considered in themselves.
Reply Obj. 3: Those ceremonies which were prescribed in the cleansing of a leper, were not ordained for the purpose of taking away the defilement of leprosy. This is clear from the fact that these ceremonies were not applied to a man until he was already healed: hence it is written (Lev. 14:3, 4) that the priest, "going out of the camp, when he shall find that the leprosy is cleansed, shall command him that is to be purified to offer," etc.; whence it is evident that the priest was appointed the judge of leprosy, not before, but after cleansing. But these ceremonies were employed for the purpose of taking away the uncleanness of irregularity. They do say, however, that if a priest were to err in his judgment, the leper would be cleansed miraculously by the power of God, but not in virtue of the sacrifice. Thus also it was by miracle that the thigh of the adulterous woman rotted, when she had drunk the water "on which" the priest had "heaped curses," as stated in Num. 5:19-27. ________________________
THIRD ARTICLE [I-II, Q. 103, Art. 3]
Whether the Ceremonies of the Old Law Ceased at the Coming of Christ?
Objection 1: It would seem that the ceremonies of the Old Law did not cease at the coming of Christ. For it is written (Bar. 4:1): "This is the book of the commandments of God, and the law that is for ever." But the legal ceremonies were part of the Law. Therefore the legal ceremonies were to last for ever.
Obj. 2: Further, the offering made by a leper after being cleansed was a ceremony of the Law. But the Gospel commands the leper, who has been cleansed, to make this offering (Matt. 8:4). Therefore the ceremonies of the Old Law did not cease at Christ's coming.
Obj. 3: Further, as long as the cause remains, the effect remains. But the ceremonies of the Old Law had certain reasonable causes, inasmuch as they were ordained to the worship of God, besides the fact that they were intended to be figures of Christ. Therefore the ceremonies of the Old Law should not have ceased.