I. THE RULE OF THE MAN OF GOD, THE BIBLE ALONE.
"All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness; that the man of God may be perfect, thoroughly furnished unto all good works." 2 Timothy 3:16,17
II. THE RULE OF THE ROMANIST, THE BIBLE AND TRADITION.
It is certain that the first-day Sabbath cannot be sustained by the first of these rules; for the word of God says nothing respecting such an institution."If we would have the whole rule of Christian faith and practice, we must not be content with those scriptures which Timothy knew from his infancy, that is, with the Old Testament alone; nor yet with the New Testament, without taking along with it the traditions of the apostles and the interpretation of the church, to which the apostles delivered both the book and the true meaning of it."
Note of the Douay Bible on 2Tim.3:16,17.