by St. Vincent of Lerins
If someone wants to be protected from tricks and remain healthy in the faith, he must confine his faith first to the authority of the Holy Scriptures, and secondly to the Tradition of the Church.
But someone may ask, is not the canon of Scripture sufficient for everything, and why should we add thereto the authority of Tradition?
This is because not everyone understands the Scriptures in the same way, but one explains them this way and another that way, so that it is possible to get therefrom as many thoughts as there are heads. Therefore it is necessary to be guided by the understanding of the Church …
What is tradition? It is that which has been understood by everyone, everywhere and at all times … that which you have received, and not that which you have thought up … So then, our job is not to lead religion where we wish it to go, but to follow it where it leads, and not to give that which is our own to our heirs, but to guard that which has been given to us.
St. Vincent of Lerins, Notes of a Pilgrim