from JND Kelly, “Early Christian Doctrines”
“IN the fourth and fifth centuries little or no attempt was made, in East or West, to work out a systematic sacramental theology. The universal, if somewhat vague, assumption was [up to this point] that the sacraments were outward and visible signs marking the presence of an invisible, but none the less genuine, grace. Chrysostom, for example, pointed out that, in order to understand the mysteries (by these he meant baptism and the eucharist), we must study them with the intellectual eye, attending to what the Lord promised rather than what sense perceives. According to Theodore of Mopsuestia,‘every sacrament is the indication, by means of signs and symbols, of invisible and ineffable realities‘; while the late fifth-century Pseudo-Dionysius stated that ‘the sensible rites are representations of intelligible things, and conduct and guide us to them’. Ambrose similarly distinguished the external ritual from the unseen grace or presence. The former, he pointed out, carries with it a symbolism which corresponds to man’s twofold nature, and this explains its efficacy. So in baptism water washes the body, while the soul is cleansed by the Spirit; in the eucharist what is perceived after the consecration is only a sign of what is actually there. Augustine lays particular stress on this contrast. ‘The sacrament itself’, he declares, ‘is one thing, and the power (virtus) of the sacrament another.’ Elsewhere he writes of the eucharistic bread and wine, ‘So they are called sacraments because one thing is seen in them, another understood. What is seen has a bodily appearance, but what is understood has spiritual fruit.’ In baptism the water serves as the sacrament of the grace imparted, but the grace itself is invisibly operated by the Holy Spirit. . . . . . .
Secondly, it is clear that much thought was given in this period to the efficient cause linking the spiritual gift with the outward, perceptible sign. According to Cyril of Jerusalem,a once the Trinity has been invoked (he uses the term epiclipsis) , the baptismal water possesses sanctifying power in view of the fact that it is no longer mere water, but water united with the Holy Spirit, Who acts in and through it. So Gregory Nazianzen bases the efficacy of baptism on the Spirit, and Basil declares that ‘if the baptismal waters have any grace, they derive it, not from their own nature, but from the presence of the Holy Spirit’. Ambrose follows Basil in teaching that the efficacy of the sacrament springs from the presence of the Holy Spirit in the water. The Trinitarian formula, however, is also indispensable: ‘unless the catechumen is baptized in the name of the Father and of the Son and of the Holy Spirit, he cannot receive the remission of sins or imbibe the gift of spiritual grace’. For Augustine the operative factor seems to have been the candidate’s belief in the Trinity as expressed in his answers to the threefold baptismal interrogations. ‘Take away the word’, he remarks ‘and what is the water but water? When the word is added to the element, it becomes a sacrament.’ He goes on to explain that it is not merely the uttering of the word, but the word considered as a vehicle of faith, that endows the water with saving power; and the context, with its references to Rom. 10:8-10, and 1 Peter 3:21 makes it plain that he is thinking of the triple questionnaire and the confession of faith made in response to it. . . . . . . two ideas, that the grace contained in sacraments is God’s gift and has nothing to do with the officiant as such, and that its production is tied to the divinely prescribed formula rehearsed by the minister, go a long way towards the so-called ex opere operato doctrine of sacraments, i.e. that they are signs which actually and automatically realize the grace they signify.”