Okay…I know there are plenty of threads about this, but this is an offshoot of the "Why do Protestants accuse Catholics of not being Bible followers?" thread.
In it Ginger2 said “name one thing that is missing from the Bible,” and “My claim is that the Catholic Church cannot tell me anything necessary to my personal salvation that is not already in the Bible.” I am hoping to expand on this a little bit.
First, from the Catechism, so we have an understanding of what the Church teaches:
One common source. . .
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."40 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”.41
. . . two distinct modes of transmission
81 "Sacred Scripture is the speech of God as it is put down in writing under the breath of the Holy Spirit."42
"And [Holy] *Tradition *transmits in its entirety the Word of God which has been entrusted to the apostles by Christ the Lord and the Holy Spirit. It transmits it to the successors of the apostles so that, enlightened by the Spirit of truth, they may faithfully preserve, expound and spread it abroad by their preaching."43
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."44
The important thing stated here is that they are “bound closely together.” You can’t take one without the other.
The other premise I offer is from the Bible, Phil 2:12-15:
To ask “what is missing in the Bible for salvation,” to me is not a good question. It is like asking ‘what is the absolute minimum I have to do to pass this class’ in school.
I believe the best examples of this are the Sacraments. They are in the Bible, but the understanding and practice of them comes from Tradition. This is why the two are “bound closely together.” You need both, with the guidance of the Magisterium, to come to the fullness of the Truth.