Catholicism teaches that the doctrines contained in Sacred Scripture (the Bible) and Sacred Tradition (the Church) are authoritative because God’s revelation is the source of both. The Catechism puts it this way: “Sacred Tradition and Sacred Scripture make up a single sacred deposit of the word of God” (97).

This means that “both Scripture and Tradition must be accepted and honored with equal sentiments of devotion and reverence” (82).

To some Protestants, this might sound blasphemous. The idea that anything the Church says could be on the same level as Scripture just doesn’t make sense. After all, only the Bible was inspired by God, right? How, then, can Catholics say that both must be reverenced equally?

More importantly, what happens if they come into conflict? The Protestant, in principle, does not face these difficulties because the Bible is said to hold the supreme place. As the ultimate and final level of religious authority, according to sola scriptura, when the Bible comes into conflict with any other authority it must be declared the winner.

In Principle, Protestants Agree: Not everything that Christians are to believe must be taught explicitly in Scripture.

In Particular, Catholicism Affirms: Some things that Christians are to believe have been taught outside of Scripture.

https://www.catholic.com/tract/pillar-of-fire-pillar-of-truth