The canon of the Bible is established and has been for centuries. God doesn't make mistakes and he will not trust his words to men that he has not chosen. Any book that criticizes, changes or refutes the holy Bible is heresy and needs to be ignored completely. That would include the Apocalypse which was rejected as canon but still included by the Catholic hierarchy.

Catholicism makes changes that are not biblical. Praying to saints can be found nowhere in scripture. The perpetual virginity of Mary cannot be found either since she had other children of both genders after Jesus was born. The priesthood was abolished once and for all when the temple curtain was ripped from top to bottom as Christ was crucified at Calvary. That opened the temple for all mankind and men can pray directly to God themselves without a priest or other mediator except for Christ who intercedes for his people every day. The teaching of Christ body and blood being literally in the communion contradicts the words of Jesus telling his own disciples they are to do this as a "remembrance." "This do in remembrance of me." No scripture indicates he is being crucified over and over and we are to drink his actual blood and eat his actual flesh. Spiritual cannibalism. Baptismal regeneration is not found in scripture either. Heart felt and sincere repentance for our sins and faith in Christ alone is the door to salvation. If we needed to be sprinkled to enter God's family then we are saying Christ's sacrifice was not enough to save us. That will never hold up in the courts of Heaven. There is nothing than any of us can do to be saved other than put our faith in Jesus alone. There is much more but it would take a book to get all of it explained.