There are tremendous implications here for how we understand the Nicene confession of "one, holy, catholic, and apostolic Church," don't you think?
If by the concept of a "true religion" we mean truth which belongs to
religion in itself and as such, it is just as unattainable as a "good man,"
if by goodness we mean something which man can achieve on his own
initiative. No religion is true. It can only become true. ...And it can
become true only in a way in which man is justified, from without...Like justified man, religion is a creature of grace.
(Church Dogmatics, I, 2, p. 325-326)