Over the centuries, three widely recognized principles were used to validate the writings that constituted divine, inspired revelation. First, the writing had to have been authored by a recognized prophet or apostle or by someone associated with one, as in the case of the books of Mark, Luke, Hebrews, James, and Jude. Second, the writing could not disagree with or contradict any previous Scripture. Third, the church had to display a general consensus that a writing was an inspired book.