Why did Catholics add books to the Bible when the book of Revelations warn against it?

Answer 1

AnswerBooks have been added to and removed from the Bible since pretty much when it was created, simply to suit a particular group of people who was changing it at the time. Besides this, when has any Christian church actually done what its holy book suggests, recommends or commands?
AnswerFirst, the early Christians were not really sure what books were in the Hebrew canon until the fourth century, when Bishop Melito of Sardis went to Palestine to discover which Hebrew books belonged in the canon. By then, the Church had already established a tradition as to what books they felt were part of the Old Testament. During the subsequent Protestant Reformation, books were removed from the Protestant Old Testament.

The authority of the Book of Revelation was already in question in antiquity. Its authorship of these seven books are indeed the ones questioned by Origen, about 200 CE. Bishop Eusebius of Caesaria, a leading church historian in the fourth century, was uncertain whether it should be part of the Christian New Testament, writing that some of his contemporaries rejected it.

Martin Luther denigrated Revelation, and the important early Protestant leader, Calvin, rejected it. Other Protestant leaders treated Revelation as a disputed book.