answer the question ebb tide. Does the fraud with the turned around collar have the power to forgive others sins?
There have been 100s of apparitions of Mary throughout history and they are not 100% consistent in their teachings? If an apparition ends of teaching a false doctrine with a prophecy that comes true was that from Mary?
What if an angel told someone to go to a Mosque and afterwards they were healed of cancer? How about the 100s of people who claim to speak with God on a regular basis? You then have people like Joseph Smith, Ellen White, Charles Russell etc Why not trust their revelations?
The whole point of this is that we must have one solid framework to base all non-scriptural revelations and that of course is the Bible. We can know this because all of the NT was either written by someone who witnessed the death, burial, and resurrection of Christ directly, or it was someone who knew a witness personally. (Yes there is the debate of authorship of Hebrews, but the writing style, depth of Jewish knowledge, and harmony with other scripture strongly points to Paul)