QUOTATION: The Rule of Faith

It always was, and is today, the usual practice of Catholics to test the true faith by two methods; first, by the authority of the divine Canon, and then, by the tradition of the Catholic Church. Not that the Canon is insufficient in itself in each case. But, because more interpreters of the Divine Word make use of their own arbitrary judgment and thus fall into various opinions and errors, the understanding of Holy Scripture must conform to the single rule of Catholic teaching—and this especially in regard to those questions upon which the foundations of all Catholic dogma are laid.

--St. Vincent of Lérins, Commonitory for the Antiquity and Universality of the Catholic Faith

QUOTATION: Sacred Tradition Equal to Scripture

Of the dogmas and proclamations preserved in the Church, some we possess from written teaching, while others we have received in secret from the Tradition of the Apostles; these both have the same validity for true religion. And no one will gainsay these points, at least if he is even moderately versed in ecclesiastical institutions.

--St. Basil the Great

QUOTATION: Sacred Tradition

The very tradition, teaching, and faith of the Catholic Church from the beginning, which the Lord gave, was preached by the apostles and was preserved by the Fathers. On this was the Church founded, and if anyone departs from this, he neither is, nor any longer ought to be called, a Christian.

-- St. Athanasius