In 2 Timothy 3:16-17, we read "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 complete, thoroughly equipped for every good work." If scripture is profitable for doctrine, it makes sense to get your doctrine from scripture. If scripture is useful for reproof, it makes sense to use it to reprove a person, organisation or belief. If scripture is good for correction, it makes sense to use it to correct falsehoods. If scripture is useful for instruction in righteousness, that the man of God may be complete and equipped for every good work, you cannot logically interpret it in any other way than that you need nothing else but the scriptures to live a complete and Godly life, and that there is not a single good work that the Bible does not thoroughly equip you for.
But the Catholic Church vehemently disagrees. Rather than using the scriptures for all of the above, Catholics use their Church to judge the Bible. Some Catholics even believe the Church is what gives the Bible its authority, rather than the Bible giving the Church its authority. Thus, the official Catholic position, regardless of exactly how devout the individual Catholic may be, must necessarily be that 2 Timothy 3:16-17 is wrong.
But of course, most of them don't flat out admit that! The ones that do are quite rare. But to flat out admit that they believe anything in the Bible is wrong is not in step with official Catholic doctrine. Rather, the approach the Catholic Church takes is to cast doubt on man's ability to correctly handle the scriptures without their help.
According to the Council of Trent, held between 1545 and 1563, "...no one, relying on his own skill, shall,--in matters of faith, and of morals pertaining to the edification of Christian doctrine,--wresting the sacred Scripture to his own senses, presume to interpret the said sacred Scripture contrary to that sense which holy mother Church,--whose it is to judge of the true sense and interpretation of the holy Scriptures,--hath held and doth hold..."
For the time being, I am extremely hesitant to call Catholicism a cult. It would be particularly unorthodox for me to do so, given that the majority do not classify it as such. But quotes like this make me think that the main reason it cannot be classed as a cult is because it is too big. The above is the same strategy employed by literally every other "Christian" cult in existence. "Don't use the Bible to judge my teachings, use my teachings to interpret the Bible."
And so this is the general strategy of Catholic apologists at most levels. "It's not that the Bible is opposed to Catholicism, it's just that you're interpreting it wrong." But the only reason Catholics ever give to say that your interpretation is wrong is that, to use the words of the Council of Trent, your interpretation is, "contrary to that sense which holy mother Church hath held and doth hold". Which isn't always true, by the way. Catholicism evolves over time, so what the Church "doth hold" is not necessarily what the Church "hath held". But that's just a side note. The main point is that Catholics try to argue that you cannot interpret the Bible without their help, thus apparently disarming any Biblical refutation of a Catholic doctrine. But this is blatant circular reasoning! You must first assume Catholic authority before you accept the idea that the Catholic Church alone has the authority to interpret the Bible. A logical person knows that the Bible is a book. If the Bible says black, and the Catholic Church says white, the Catholic Church can't make the Bible say white. White is the wrong answer, and you can tell that simply by the fact the Bible says black, and that it does so in black and white.
This was the policy of the Bereans in Acts 17. Obviously, they had no concept of the Catholic Church, because it did not yet exist, and would not exist for at least another century. But what the Bereans did have a concept of was the scriptures. They knew that the scriptures were true, and thus, relying on their own skills, wresting the sacred Scripture to their own senses, they presumed to interpret the aforementioned sacred Scripture to judge whether or not Paul was telling the truth. For this, they were called fair minded.
Catholics can learn a lot from the Bereans. As an Apostle, Paul had quite a bit of authority. He had seen the risen Lord (1 Corinthians 9:1), and even during his own lifetime, some of his writings were acknowledged as scripture (despite Catholic claims that the Bible was non-existent for nearly 400 years after Christ) by none other than Peter (2 Peter 3:15-16), whom Catholics claim was their first Pope. In other words, no matter which way you cut the cake, Paul must have had just as much authority as the Catholic Church claims to have in the modern day, if not more. And yet, in Acts 17:11, Luke commended the Bereans as "fair minded" for searching the scriptures to test Paul!
Paul himself was not opposed to being tested. In fact, in 1 Thessalonians 5:21, Paul commanded the church in Thessalonica to test all things, and hold on to that which is good. Paul also declared that even he, the other Apostles, even an angel from Heaven, could not change the Gospel (Galatians 1:8). So, now we have a scriptural command (which Catholics acknowledge is inspired by God Himself, in accordance with 2 Timothy 3:16) from a man whose epistles are acknowledged as scripture by the supposed first Pope, along with a rather helpful example of when a group of people did just that. All of this points to two things.
First, it points us to the fact that even in Catholic theology, the Bible must necessarily be used to test the Catholic Church. Second, it points us to the fact that the Catholic Church is contradictory, because it also claims that the Church must necessarily be used to interpret the Bible, thus making it 100% impossible to test the Church against it! But there is a better way. Simply taking the Bible as it is, Christians do not need to restrain themselves from testing their teachers against the scriptures. When I read the Bible, I read it like the Bereans did: As a book. The Lord has blessed man with two amazing gifts: A fully functioning brain, and fully complete scriptures. Combining the two enables anyone to see that the Catholic Church is a complete counterfeit of Christianity. Only by asking you to forego the use of either your mind, your Bible, or both can the Catholic Church possibly survive a test, but passing a rigged test is not passing. It is merely a veiled confession that you could not pass if it was not rigged.