What
then shall the Catholic do if some portion of the Church detaches
itself from communion of the universal Faith? What other choice can
he make – and if some new contagion attempts to poison, no longer
a small part of the Church, but the whole Church at once, then his
great concern will be to attach himself to antiquity (Tradition)
which can no longer be led astray by any lying novelty.
--
Saint Vincent of Lerins