Article — Merkelbach, Summa Theologiae Moralis
Article I: On the Various Ministers of the Sacraments
St. Thomas III, q. 64, a. 3 and 7.
73. Christ as man is the principal minister confecting and dispensing the sacraments, not indeed by Himself, but through visible legates who, by power received from Him, perform the visible sacraments in His name. This is evident from various places of Scripture (John I, 33; Eph. V, 25; I Cor. I, 12; Mt. XXVIII, 19) and from the very form of the Eucharist.
Hence not only Christ and the sacraments themselves, but also the ministers are true instrumental causes of sanctification. And therefore, just as He could determine the sacramental signs themselves, so also Christ could determine the person or minister by whom the signs would be effected, and indeed in such a way that, if this person of the minister were lacking, the sign would not be valid nor would it produce its effects. Whence those are secondary ministers who are determined by Christ the institutor.
74. The secondary ministers in fact are:
- By ordinary law, wayfaring men, as being similar at once to Christ and to the recipients, using reason, whom alone Christ addresses when in the Gospel He treats of ministers (cf. Mt. XXVIII, 19 for Baptism; Luke XXII, 19 for the Eucharist; John XX, 23 for Penance; Jas. V, 14 for Extreme Unction; I Cor. IV, 1 sq. and Eph. IV, 8 sq. generally); - but not Angels or separated souls, although extraordinarily Christ could assign this power to them: for He has not bound His power to ministers or signs.
- Yet not all wayfarers; rather the ordinary ministers and ministers of solemnity, acting from office, are those who are specially consecrated for this through the sacrament of Order, as the Council of Trent defines, sess. 7, can. 10 against the Protestants (Eph. IV, 11). Matrimony is excepted, in which the contracting parties are the ministers.
- The extraordinary minister and minister of necessity can be a layperson in Baptism and in the distribution of the Eucharist.
Let it be noted that no one can minister a sacrament to himself, except the Eucharist.