““the amount of grace conferred by a Sacrament in each instance depends (i) on the eternal decree of God, who has endowed each Sacrament with a definite measure of grace, and (2) on the disposition and co-operation of the recipient. Note, however, that the Sacraments are efficacious ex opere operate, and con sequently the disposition of the recipient is not the cause of grace, but merely a condition of a richer outpouring of the same, just as the dryness of a stick of wood is not the cause of its burning, but a condition of its being more rapidly consumed by the flames.””