4 But I trust that the Church, by the light of her doctrine, will so enlighten the world's vain wisdom, that, even though it accept not the mystery of the faith, it will recognise that in our conflict with heretics we, and not they, are the true representatives of that mystery. For great is the force of truth; not only is it its own sufficient witness, but the more it is assailed the more evident it becomes; the daily shocks which it receives only increase its inherent stability.
It is the peculiar property of the Church that when she is buffeted she is triumphant, when she is assaulted with argument she proves herself in the right, when she is deserted by her supporters she holds the field. It is her wish that all men should remain at her side and in her bosom; if it lay with her, none would become unworthy to abide under the shelter of that august mother, none would be cast out or suffered to depart from her calm retreat. But when heretics desert her or she expels them, the loss she endures, in that she cannot save them, is compensated by an increased assurance that she alone can offer bliss.
This is a truth which the passionate zeal of rival heresies brings into the clearest prominence. The Church, ordained by the Lord and established by His Apostles, is one for all; but the frantic folly of discordant sects has severed them from her. And it is obvious that these dissensions concerning the faith result from a distorted mind, which twists the words of Scripture into conformity with its opinion, instead of adjusting that opinion to the words of Scripture. And thus, amid the clash of mutually destructive errors, the Church stands revealed not only by her own teaching, but by that of her rivals.
They are ranged, all of them, against her; and the very fact that she stands single and alone is her sufficient answer to their godless delusions. The hosts of heresy assemble themselves against her; each of them can defeat all the others, but not one can win a victory for itself. The only victory is the triumph which the Church celebrates over them all. Each heresy wields against its adversary some weapon already shattered, in another instance, by the Church's condemnation. There is no point of union between them, and the outcome of their internecine struggles is the confirmation of the faith.
Source: On the Trinity (New Advent)