To the eye of faith, and so of theology, there is no authentic Christianity apart from the Catholic Church, and the Church has an inward pattern or design centred on Christ. I say ‘inward’ to imply that this pattern is not visible to the historian as such. History can only show the development of the Church as an institution making certain claims: to interpret these historical data in terms of that pattern is the work of theology.

The pattern might be represented by two lines drawn from a central point. The point is Christ, both Saviour and Word; the lines are a line of ‘grace’ passing through sacraments to the souls of men, and a line of truth passing through faith and teaching to their minds. Grace and truth combine in Christ, and of this fulness we have all received; but grace in one way and truth in another. Life and light, identical in Christ, reach us through distinct media within the one Church: grace through the sacraments, and supremely in the Eucharist; truth through faith and the Church’s articulation of the faith and in the rules wherewith she applies it to the details of conduct. In both communications the Church, we believe, is necessary. But the manner of her mediation differs in each case.

Where sanctifying grace is concerned the Church is purely God’s instrument, in the most limited sense of the term. Her task here is simply to effect the sacred sign, to consecrate, for example, the host and administer it; the rest—granted the recipient’s response—is all God’s work. The Church here is a mere vehicle of a divine action; and this in virtue of the power conferred on every priest at ordination. And so limited is the human share in this sanctification through the sacraments that the priest’s personal moral quality makes no difference at all to the degree of grace transmitted.