On the contrary, The institutor of anything is he who gives it strength and power: as in the case of those who institute laws. But the power of a sacrament is from God alone, as we have shown above (A[1]; Q[62], A[1]). Therefore God alone can institute a sacrament.
I answer that, As appears from what has been said above (A[1]; Q[62], A[1]), the sacraments are instrumental causes of spiritual effects. Now an instrument has its power from the principal agent. But an agent in respect of a sacrament is twofold; viz. he who institutes the sacraments, and he who makes use of the sacrament instituted, by applying it for the production of the effect. Now the power of a sacrament cannot be from him who makes use of the sacrament: because he works but as a minister. Consequently, it follows that the power of the sacrament is from the institutor of the sacrament. Since, therefore, the power of the sacrament is from God alone, it follows that God alone can institute the sacraments.
Reply to Objection 1: Human institutions observed in the sacraments are not essential to the sacrament; but belong to the solemnity which is added to the sacraments in order to arouse devotion and reverence in the recipients. But those things that are essential to the sacrament, are instituted by Christ Himself, Who is God and man. And though they are not all handed down by the Scriptures, yet the Church holds them from the intimate tradition of the apostles, according to the saying of the Apostle ( 1 Cor. 11:34 ): "The rest I will set in order when I come."
Reply to Objection 2: From their very nature sensible things have a certain aptitude for the signifying of spiritual effects: but this aptitude is fixed by the Divine institution to some special signification. This is what Hugh of St. Victor means by saying (De Sacram. i) that "a sacrament owes its signification to its institution." Yet God chooses certain things rather than others for sacramental signification, not as though His choice were restricted to them, but in order that their signification be more suitable to them.
Reply to Objection 3: The apostles and their successors are God's vicars in governing the Church which is built on faith and the sacraments of faith. Wherefore, just as they may not institute another Church, so neither may they deliver another faith, nor institute other sacraments: on the contrary, the Church is said to be built up with the sacraments "which flowed from the side of Christ while hanging on the Cross."
Whether Christ as man had the power of producing the inward sacramental effect?
Objection 1: It seems that Christ as man had the power of producing the interior sacramental effect. For John the Baptist said ( Jn. 1:33 ): "He, Who sent me to baptize in water, said to me: He upon Whom thou shalt see the Spirit descending and remaining upon Him, He it is that baptizeth with the Holy Ghost." But to baptize with the Holy Ghost is to confer inwardly the grace of the Holy Ghost. And the Holy Ghost descended upon Christ as man, not as God: for thus He Himself gives the Holy Ghost. Therefore it seems that Christ, as man, had the power of producing the inward sacramental effect.
Objection 2: Further, our Lord said ( Mat. 9:6 ): "That you may know that the Son of Man hath power on earth to forgive sins." But forgiveness of sins is an inward sacramental effect. Therefore it seems that Christ as man produces the inward sacramental effect.
Objection 3: Further, the institution of the sacraments belongs to him who acts as principal agent in producing the inward sacramental effect. Now it is clear that Christ instituted the sacraments. Therefore it is He that produces the inward sacramental effect.
Objection 4: Further, no one can confer the sacramental effect without conferring the sacrament, except he produce the sacramental effect by his own power. But Christ conferred the sacramental effect without conferring the sacrament; as in the case of Magdalen to whom He said: "Thy sins are forgiven Thee" ( Lk. 7:48 ). Therefore it seems that Christ, as man, produces the inward sacramental effect.
Objection 5: Further, the principal agent in causing the inward effect is that in virtue of which the sacrament operates. But the sacraments derive their power from Christ's Passion and through the invocation of His Name; according to 1 Cor. 1:13 : "Was Paul then crucified for you? or were you baptized in the name of Paul?" Therefore Christ, as man, produces the inward sacramental effect.
On the contrary, Augustine (Isidore, Etym. vi) says: "The Divine power in the sacraments works inwardly in producing their salutary effect." Now the Divine power is Christ's as God, not as man. Therefore Christ produces the inward sacramental effect, not as man but as God.
I answer that, Christ produces the inward sacramental effect, both as God and as man, but not in the same way. For, as God, He works in the sacraments by authority: but, as man, His operation conduces to the inward sacramental effects meritoriously and efficiently, but instrumentally. For it has been stated (Q[48], AA[1],6; Q[49], A[1]) that Christ's Passion which belongs to Him in respect of His human nature, is the cause of justification, both meritoriously and efficiently, not as the principal cause thereof, or by His own authority, but as an instrument, in so far as His humanity is the instrument of His Godhead, as stated above (Q[13], AA[2],3; Q[19], A[1]).
Nevertheless, since it is an instrument united to the Godhead in unity of Person, it has a certain headship and efficiency in regard to extrinsic instruments, which are the ministers of the Church and the sacraments themselves, as has been explained above (A[1]). Consequently, just as Christ, as God, has power of "authority" over the sacraments, so, as man, He has the power of ministry in chief, or power of "excellence." And this consists in four things. First in this, that the merit and power of His Passion operates in the sacraments, as stated above (Q[62], A[5]). And because the power of the Passion is communicated to us by faith, according to Rom. 3:25 : "Whom God hath proposed to be a propitiation through faith in His blood," which faith we proclaim by calling on the name of Christ: therefore, secondly, Christ's power of excellence over the sacraments consists in this, that they are sanctified by the invocation of His name. And because the sacraments derive their power from their institution, hence, thirdly, the excellence of Christ's power consists in this, that He, Who gave them their power, could institute the sacraments. And since cause does not depend on effect, but rather conversely, it belongs to the excellence of Christ's power, that He could bestow the sacramental effect without conferring the exterior sacrament. Thus it is clear how to solve the objections; for the arguments on either side are true to a certain extent, as explained above.
Whether Christ could communicate to ministers the power which He had in the sacraments?
Objection 1: It seems that Christ could not communicate to ministers the power which He had in the sacraments. For as Augustine argues against Maximin, "if He could, but would not, He was jealous of His power." But jealousy was far from Christ Who had the fulness of charity. Since, therefore, Christ did not communicate His power to ministers, it seems that He could not.
Objection 2: Further, on Jn. 14:12 : "Greater than these shall he do," Augustine says (Tract. lxxii): "I affirm this to be altogether greater," namely, for a man from being ungodly to be made righteous, "than to create heaven and earth." But Christ could not communicate to His disciples the power of creating heaven and earth: neither, therefore, could He give them the power of making the ungodly to be righteous. Since, therefore, the justification of the ungodly is effected by the power that Christ has in the sacraments, it seems that He could not communicate that power to ministers.
Objection 3: Further, it belongs to Christ as Head of the Church that grace should flow from Him to others, according to Jn. 1:16 : "Of His fulness we all have received." But this could not be communicated to others; since then the Church would be deformed, having many heads. Therefore it seems that Christ could not communicate His power to ministers.
On the contrary, on Jn. 1:31 : "I knew Him not," Augustine says (Tract. v) that "he did not know that our Lord having the authority of baptizing . . . would keep it to Himself." But John would not have been in ignorance of this, if such a power were incommunicable. Therefore Christ could communicate His power to ministers.
I answer that, As stated above (A[3]), Christ had a twofold power in the sacraments. one was the power of "authority," which belongs to Him as God: and this power He could not communicate to any creature; just as neither could He communicate the Divine Essence. The other was the power of "excellence," which belongs to Him as man. This power He could communicate to ministers; namely, by giving them such a fulness of grace---that their merits would conduce to the sacramental effect---that by the invocation of their names, the sacraments would be sanctified---and that they themselves might institute sacraments, and by their mere will confer the sacramental effect without observing the sacramental rite. For a united instrument, the more powerful it is, is all the more able to lend its power to the separated instrument; as the hand can to a stick.
Reply to Objection 1: It was not through jealousy that Christ refrained from communicating to ministers His power of excellence, but for the good of the faithful; lest they should put their trust in men, and lest there should be various kinds of sacraments, giving rise to division in the Church; as may be seen in those who said: "I am of Paul, I am of Apollo, and I of Cephas" ( 1 Cor. 1:12 ).
Reply to Objection 2: This objection is true of the power of authority, which belongs to Christ as God. At the same time the power of excellence can be called authority in comparison to other ministers. Whence on 1 Cor. 1:13 : "Is Christ divided?" the gloss says that "He could give power of authority in baptizing, to those to whom He gave the power of administering it."
Reply to Objection 3: It was in order to avoid the incongruity of many heads in the Church, that Christ was unwilling to communicate to ministers His power of excellence. If, however, He had done so, He would have been Head in chief; the others in subjection to Him.
Whether the sacraments can be conferred by evil ministers?
Objection 1: It seems that the sacraments cannot be conferred by evil ministers. For the sacraments of the New Law are ordained for the purpose of cleansing from sin and for the bestowal of grace. Now evil men, being themselves unclean, cannot cleanse others from sin, according to Ecclus. 34:4 : "Who [Vulg.: 'What'] can be made clean by the unclean?" Moreover, since they have not grace, it seems that they cannot give grace, for "no one gives what he has not." It seems, therefore, that the sacraments cannot be conferred by wicked men.