But in regard to those observances which we carefully attend and which
the whole world keeps, and which derive not from Scripture but from
Tradition, we are given to understand that they are recommended and
ordained to be kept, either by the Apostles themselves or by plenary
councils, the authority of which is quite vital in the Church.
Catechism of the Council of Trent (1566)
Preface: Now all the doctrines in which the faithful are to be instructed
are contained in the Word of God, which is found in Scripture and
Tradition. To the study of these, therefore, the pastor should devote his
days and nights, keeping in mind the admonition of St. Paul to Timothy,
which all who have care of souls should consider as addressed to
themselves: Attend to reading, to exhortation, and to doctrine, for all
scripture divinely inspired is profitable to teach, to reprove, to correct, to
instruct injustice, that the man of God may be perfect, furnished to every
good work.
Catechism of the Catholic Church (1992)
No. 80:
Sacred Tradition and Sacred Scripture, then, are bound
closely together and communicate one with the other. For both of them,
flowing out from the same divine well-spring, come together in some
fashion to form one thing and move towards the same goal. Each of them
makes present and fruitful in the Church the mystery of Christ, who
promised to remain with his own always, to the close of the age.
No. 82:
As a result the Church, to whom the transmission and
interpretation of Revelation is entrusted, does not derive her certainty about
all revealed truths from the holy Scriptures alone. Both Scripture and
Tradition must be accepted and honored with equal sentiments of devotion
and reverence.