I answer that, The Master's definition of Order applies to Order as a sacrament of the Church. Hence he mentions two things, namely the outward sign, a "kind of seal," i.e. a kind of sign, and the inward effect, "whereby spiritual power," etc.
Reply to Objection 1: Seal stands here, not for the inward character, but for the outward action, which is the sign and cause of inward power; and this is also the sense of character in the other definition. If, however, it be taken for the inward character, the definition would not be unsuitable; because the division of a sacrament into those three things is not a division into integral parts, properly speaking; since what is reality only is not essential to the sacrament, and that which is the sacrament is transitory; while that which is sacrament and reality is said to remain. Wherefore it follows that inward character itself is essentially and principally the sacrament of Order.
Reply to Objection 2: Although in Baptism there is conferred a spiritual power to receive the other sacraments, for which reason it imprints a character, nevertheless this is not its principal effect, but the inward cleansing; wherefore Baptism would be given even though the former motive did not exist. On the other hand, order denotes power principally. Wherefore the character which is a spiritual power is included in the definition of Order, but not in that of Baptism.
Reply to Objection 3: In Baptism there is given a certain spiritual potentiality to receive, and consequently a somewhat passive potentiality. But power properly denotes active potentiality, together with some kind of preeminence. Hence this definition is not applicable to Baptism.
Reply to Objection 4: The word "order" is used in two ways. For sometimes it denotes the relation itself, and thus it is both in the inferior and in the superior, as the objection states; but it is not thus that we use the word here. On the other hand, it denotes the degree which results in the order taken in the first sense. And since the notion of order as relation is observed where we first meet with something higher than another, it follows that this degree of pre-eminence by spiritual power is called Order.
Whether Order is a sacrament?
Objection 1: It would seem that Order is not a sacrament. For a sacrament, according to Hugh of St. Victor (De Sacram. i) "is a material element." Now Order denotes nothing of the kind, but rather relation or power; since Order is a part of power according to Isidore. Therefore it is not a sacrament.
Objection 2: Further, the sacraments do not concern the Church triumphant. Yet Order is there, as in the angels. Therefore it is not a sacrament.
Objection 3: Further, just as spiritual authority, which is Order, is given by means of consecration, so is secular authority, since kings also are anointed, as stated above (Q[19], A[3], ad 2). But the kingly power is not a sacrament. Therefore neither is order of which we speak now.
On the contrary, It is mentioned by all among the seven sacraments of the Church.
Further, "the cause of a thing being such, is still more so." Now Order is the cause of man being the dispenser of the other sacraments. Therefore Order has more reason for being a sacrament than the others.
I answer that, As stated above (Q[29], A[1]; TP, Q[60]), a sacrament is nothing else than a sanctification conferred on man with some outward sign. Wherefore, since by receiving orders a consecration is conferred on man by visible signs, it is clear that Order is a sacrament.
Reply to Objection 1: Although Order does not by its name express a material element, it is not conferred without some material element.
Reply to Objection 2: Power must needs be proportionate to the purpose for which it is intended. Now the communication of divine things, which is the purpose for which spiritual power is given, is not effected among the angels by means of sensible signs, as is the case among men. Hence the spiritual power that is Order is not bestowed on the angels by visible signs, as on men. Wherefore Order is a sacrament among men, but not among angels.
Reply to Objection 3: Not every blessing or consecration given to men is a sacrament, for both monks and abbots are blessed, and yet such blessings are not sacraments, and in like manner neither is the anointing of a king; because by such blessings men are not ordained to the dispensing of the divine sacraments, as by the blessing of Order. Hence the comparison fails.
Whether the form of this sacrament is suitably expressed?
Objection 1: It would seem that the form of this sacrament is unsuitably set forth in the text (Sent. iv, D, 24). Because the sacraments take their efficacy from their form. Now the efficacy of the sacraments is from the divine power, which works our salvation in them in a most hidden manner. Therefore the form of this sacrament should include a mention of the divine power by the invocation of the Trinity, as in the other sacraments.
Objection 2: Further, to command pertains to one who has authority. Now the dispenser of the sacrament exercises no authority, but only ministry. Therefore he should not use the imperative mood by saying: "Do" or "Receive" this or that, or some similar expression.
Objection 3: Further, mention should not be made in the sacramental form, except of such things as are essential to the sacrament. But the use of the power received is not essential to this sacrament, but is consequent upon it. Therefore it should not be mentioned in the form of this sacrament.
Objection 4: Further, all the sacraments direct us to an eternal reward. But the forms of the other sacraments make no mention of a reward. Therefore neither should any mention be made thereof in the form of this sacrament, as in the words: "Since thou wilt have a share, if faithfully," etc.
I answer that, This sacrament consists chiefly in the power conferred. Now power is conferred by power, as like proceeds from like; and again power is made known by its use, since powers are manifested by their acts. Wherefore in the form of order the use of order is expressed by the act which is commanded; and the conferring of power is expressed by employing the imperative mood.
Reply to Objection 1: The other sacraments are not ordained chiefly to effects similar to the power whereby the sacraments are dispensed, as this sacrament is. Hence in this sacrament there is a kind of universal communication. Wherefore in the other sacraments something is expressed on the part of the divine power to which the effect of the sacrament is likened, but not in this sacrament.
Reply to Objection 2: [There is a special reason why this sacrament, rather than the others, is conferred by employing the imperative mood. For]* although the bishop who is the minister of this sacrament has no authority in respect of the conferring of this sacrament, nevertheless he has some power with regard to the power of Order, which power he confers, in so far as it is derived, from his. [*The sentence in brackets is not in the Leonine edition.]
Reply to Objection 3: The use of power is the effect of power in the genus of efficient cause, and from this point of view it has no reason to be mentioned in the definition of Order. But it is somewhat a cause in the genus of final cause, and from this point of view it can be placed in the definition of order.
Reply to Objection 4: There is here a difference between this and the other sacraments. Because by this sacrament an office or the power to do something is conferred; and so it is fitting that mention be made of the reward to be obtained if it be administered faithfully. But in the other sacraments no such office or power to act is conferred, and so no mention of reward is made in them. Accordingly the recipient is somewhat passive in relation to the other sacraments, because he receives them for the perfecting of his own state only, whereas in relation to this sacrament he holds himself somewhat actively, since he receives it for the sake of exercising hierarchical duties in the Church. Wherefore although the other sacraments, from the very fact that they give grace, direct the recipient to salvation, properly speaking they do not direct him to a reward, in the same way as this sacrament does.