The Roman Catholic organization informs that their so-called "Holy" Tradition is on a par with the written Word of God we call the Bible.
97 Sacred Tradition and Sacred Scripture make up a single sacred deposit of the Word of God" (DV 10) in which, as in a mirror, the pilgrim Church contemplates God, the source of all her riches--Catechism of the Catholic Church, 2nd Ed., © 1994/1997 United States Catholic Conference, Inc
The Bible-believing Christian rejects that claim; adding that the Scriptures don't need to be augmented by products of man's imagination.
16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
17 That the man of God may be perfect, thoroughly furnished unto all good works.--2 Timothy 3:16-17
The Catholic will say "See, it just says that it is 'profitable' not sufficient" Yes, that is true but if you were to take the time to study this passage and check out the Greek words you would find that it IS saying that the Scriptures are sufficient for all of these things. It IS Sufficient for doctrine (teachings), it IS sufficient for reproofing errors, it IS sufficient for correcting errors of believers and it IS sufficient for instruction in righteousness.
All that we need to know concerning the gospel plan of salvation is in the Bible. For the Bible, the God-breathed Word of God makes the man of God perfect or complete and thoroughly furnishes him for all good works.
An interesting fact, and one I never see Catholic apologists mentioning, is that a number of the Early Church Fathers held to this view. Could it be that the Catholic "apologists" we encounter on many Internet message boards are not as well read in early church history as they would have us believe? Or are they simply deceitful? Personally, I think both questions can be answered in the affirmative.
John Chrysostom is one of the Early Church Fathers Rome so delights in calling upon when seeking support for her heretical teachings. Did he think the Scriptures were sufficient? See for yourself:
Many other such things there are that beset our soul; and we have need of the divine remedies that we may heal wounds inflicted, and ward off those which, though not inflicted, would else be received in time to come—thus quenching afar off the darts of Satan, and shielding ourselves by the constant reading of the Divine Scriptures. It is not possible—I say, it is not possible, for any one to be secure without constant supplies of this spiritual instruction (translator's note, “Or without constantly making use of spiritual reading”). Indeed, we may congratulate ourselves (i.e. one ought to be content), if, constantly using this remedy, we ever are able to attain salvation. But when, though each day receiving wounds, we make use of no remedies, what hope can there be of salvation?...
Let us then not neglect the possession of the sacred books. For gold, whenever it becomes abundant, causes trouble to its possessors; but these books, when carefully preserved, afford great benefit to those who possess them. As also where royal arms are stored, though no one should use them, they afford great security to those who dwell there; since neither thieves nor burglars, nor any other evil-doers, dare attack that place. In the same way, where the inspired books are, from thence all satanical influence is banished, and the great consolation of right principles comes to those who live there; yea, even the very sight of these books by itself makes us slower to commit iniquity, Even if we attempt any forbidden thing, and make ourselves unclean, when we return home and see these books, our conscience accuses us more keenly, and we become less likely to fall again into the same sins. Again, if we have been stedfast in our integrity, we gain more benefit, (if we are acquainted with the word;) for as soon as one comes to the gospel, he by a mere look both rectifies his understanding and ceases from all worldly cares. And if careful reading also follows, the soul, as if initiated in sacred mysteries, is thus purified and made better, while holding converse with God through the Scriptures. “But what,” say they, “if we do not understand the things we read?” Even if you do not understand the contents, your sanctification in a high degree results from it. However, it is impossible that all these things should alike be misunderstood; for it was for this reason that the grace of the Holy Spirit ordained that tax-gatherers, and fishermen, and tent-makers, and shepherds, and goatherds, and uninstructed and illiterate men, should compose these books, that no untaught man should be able to make this pretext; in order that the things delivered should be easily comprehended by all—in order that the handicraftsman, the domestic, the widow, yea, the most unlearned of all men, should profit and be benefited by the reading. For it is not for vain-glory, as men of the world, but for the salvation of the hearers, that they composed these writings, who, from the beginning, were endued with the gift of the Holy Ghost...--F. Allen, trans., Four Discourses of Chrysostom, Chiefly on the Parable of the Rich Man and Lazarus, 3rd Sermon, sections 2-3; Longmans, Green, Reader and Dyer, 1869, pp. 62-68.
The Magisterium claims that the Scriptures are too difficult for the common herd to comprehend. That may be true, but is that a valid reason for creating a myth that the Catholic faithful are best advised to seek Scriptural enlightenment only through the filters of the Magisterium? John Chrysostom didn't think so.
But (it is asked) are the parts containing the signs and wonders and histories also clear and plain to every one? This is a pretence, and an excuse, and a mere cloak of idleness. You do not understand the contents of the book? But how can you ever understand, while you are not even willing to look carefully? Take the book in your hand. Read the whole history; and, retaining in your mind the easy parts, peruse frequently the doubtful and obscure parts; and if you are unable, by frequent reading, to understand what is said, go to some one wiser; betake yourself to a teacher; confer with him about the things said. Show great eagerness to learn; then, when God sees that you are using such diligence, He will not disregard your perseverance and carefulness; but if no human being can teach you that which you seek to know, He himself will reveal the whole...--Ibid.
If what this Early Church Father wrote is true, why then does the Roman Catholic Church appear so reluctant to encourage the billion or so Catholic faithful to study Scripture on their own? Perhaps the answer to this question was provided by Chrysostom:
The reading of the Scriptures is a great safeguard against sin; ignorance of the Scriptures is a great precipice and a deep gulf; to know nothing of the Scriptures, is a great betrayal of our salvation. This ignorance is the cause of heresies; this it is that leads to dissolute living; this it is that makes all things confused. It is impossible—I say, it is impossible, that any one should remain unbenefited who engages in persevering and intelligent reading.--Ibid.
What about that Catholic math formula in the title? Nothing to it: Magisterium plus Tradition equals the Word Of God. Sloppy algebra won't help you get into college, and sloppy theology won't help your spiritual state.
God is not a liar. The truth -- His truth -- is available to all who seek it. It is in the Holy Bible, not in manmade tradition.