The Efficacy of Baptism
As for the power of baptism, early Christians were convinced that the sacrament receives its saving power from the Christ who is risen and in glory but who died on the cross. The passion of Christ was literally the crucial event. Meditating on the spear the soldier thrust into Christ’s side (see John 19:34-35), the Church Fathers both Eastern and Western see the sacraments of baptism and the Eucharist embodied in the blood and water that gush forth. John Chrysostom (ch. 1), for instance, insists that the water came out first and then blood, since, in the order of things, baptism comes first and then the Eucharist; he then adds, “It was the soldier, then, who opened Christ’s side and dug through the rampart of the holy temple, but I am the one who has found the treasure and gotten the wealth” (Baptismal Homily 3:16).
The catechist is not breaking new ground but only handing on a tradition at least as old as the second century (see vol 6, ch. 2, Tertullian, On Baptism 9) and as far reaching as Jacob of Serugh (ch. 2, Memra 7, On the Baptism of the Law, II. 185-191). Indeed, the Council of Florence reflects this ancient tradition when, a thousand years later, its Decree for the Armenians explains that the passion of Christ is the “efficient” cause of the sacramental efficacy, including the sacrament of baptism (Mansi 31:1054). (Thomas M. Finn, Early Christian Baptism and the Catechumenate: West and East Syria [Message of the Fathers of the Church 5; Collegeville, Minn.: The Liturgical Press, 1992], 10-11)