One of the most frequent and most baseless accusations leveled is that the Church is “not Biblical”. I will show that the Church is and always has been completely true to all Scripture (the Catholic Church, of course, itself produced the canon of Scripture) in its official teaching and practice. It is often said that ignorance and prejudice are what has kept people from the Church and the former proves to be the case in many matters regarding Scripture. For starters, Protestants tend to read the Bible through the lenses formed through their church. They do not see how colored their interpretations often are, and just how many seemingly confusing and contradictory passages are brushed aside as a matter of course. Most of the large errors in Protestant theology come as a result of what I call “a theology of sound bites” - reading certain verses in isolation and not reading Scripture as a whole. What I’ve found, in contrast, is that all of Scripture is very successfully incorporated in and explained by Catholic theology. Catholic theology is incredibly beautiful in it’s end-to-end consistency and staggeringly unwavering - unchanging - through the ages as well. Though many doctrines have grown - become more precise - as they were meant to, all have their firm roots in Christ and the Apostles.
(A common criticism leveled at the Church is that her doctrines have, in fact, “changed” - but this is not true - they have only become more precise. ‘All public revelation ended with the death of the last Apostle, John.’ Nothing is ever rejected or revised, only clarified. Protestants should take note that many doctrines that they themselves accept without question, such as that of the Triune nature of God and the Incarnation, were definitively specified by Catholic ecumenical councils, several hundred years after the Resurrection.)
So, in terms of the evidence for the arguments I will put forth, the first major area is Scripture. This is obviously fitting, for the Bible is critically important to all Christians. Considering, especially, that sola scriptura is (along with sola fide, “faith alone”) is one of the two foundations of Protestantism, demonstrating that Scripture firmly supports Catholic theology provides even more impact. (It turns out that Scripture itself does not support sola scriptura - it firmly contradicts it. For but one example, see 1 Timothy 3:15 which call The Church, not “the Bible” (which didn’t yet exist), “the pillar and foundation of all truth”.)
The second are from which I draw evidence is the belief and practice of the early Church given to us by those known as the Church Fathers - the Christian leaders (priests, bishops, and popes) in the first three centuries of Christianity (for there have been priests, bishops, and a pope since the resurrection). What’s amazing to learn is that the testimony of the Fathers as to Christian doctrine and practice in the Church’s infancy is entirely Catholic in every area of Protestant disagreement - the Eucharist & the sacraments, the priesthood, the necessity of visible and concrete Church structure, Apostolic succession and the primacy of the Bishop of Rome, Purgatory and prayers for the dead, honoring saints and the Mother of Christ, the role of Apostolic Tradition, and more. The early Church was, as is the Catholic Church today, entirely sacramental, with the Eucharist as the absolute center of spiritual life. Can the relevance of these things be overstated? We are talking in some case about Fathers that knew the Apostles themselves directly, such as Polycarp and Iraneous, both of whom were disciples of John. No, we must conclude - even outside of all the other evidence - that the Christianity of these men and this time was the Christianity of the Apostles and of Christ Himself. There exists, in fact, from Apostolic times to the present a complete and total continuum of Catholic belief and practice - and this easily demonstrable fact makes the Protestant lie that the Church is not the Church of the Apostles simply untenable. We can debate about Biblical interpretation for hours, but we have tomes upon tomes telling us what the earliest Christians actually did - we have their interpretations, and to claim that this is not of value is terribly irrational. As the famous Cardinal Newman, an Anglican convert, once stated, “To be deep in history is to cease to be Protestant.”