Is the White Horse Prophecy a valid and true prophecy or is it false?
In short, it is false. There are many prophecies attributed to Joseph Smith that were written from memory, many after he was martyred. Most all of these do not stand up to scrutiny, such as the White Horse Prophecy. Joseph F. Smith, who personally knew the Prophet Joseph Smith, said flat out that “it is false.” (Smith, Joseph F., Conference Report 1918, 58) Stick with what the Scriptures and modern prophets have given us through proper Church channels and you won’t go wrong.