Nature of a Sacrament

(Summa Theologica, III, qq. 60-65.)

Nature of a Sacrament.—In the New Law a Sacrament is an outward sign instituted permanently by Christ to signify and convey grace.

(a) The internal cause or essence of a Sacrament is the outward sign, which has two parts. The indeterminate part or matter is a visible object (e.g., the water of Baptism, the chrism of Confirmation, the bread and wine of the Eucharist, the oil of Extreme Unction, the imposition of hands in Orders) or a perceptible act that looks to another act for its perfectionment (e.g., the confession, etc., of the penitent in penance; the giving of oneself as spouse in Matrimony). The determining part, or form, is either the sacred formula spoken over the material element (e.g., in Baptism the words “I baptize thee, etc.”) or an act that completes another act (e.g., the acceptance of another as spouse in Matrimony). As the matter must be visible or otherwise sense-perceptible, so the form must be audible or at least (in Matrimony) equivalently audible; for a Sacrament is a sensible sign. The words are audible when they are heard or are capable of being heard at least by the minister.

(b) The external efficient cause or instituter of the Sacraments is Christ, the founder of the New Testament religion and the productive and meritorious author of grace as our God and Saviour.

(c) The external final cause or purpose of the Sacraments is to symbolize outwardly by their rite and to work inwardly by their instrumental virtue the application of Christ’s redemption in the soul of properly disposed recipients. It is the nature of Baptism and Penance (Sacraments of the Dead) to produce first grace or forgiveness, of the others to produce second grace or increase of holiness (Sacraments of the Living). Furthermore, three of the Sacraments (Baptism, Confirmation, Orders) have a second effect, since they sign the soul with the indelible character of member or soldier or minister of Christ, and hence these Sacraments cannot be repeated.