11 And the vision of all is become unto you as the words of a book that is sealed, which men deliver to one that is learned, saying, Read this, I pray thee: and he saith, I cannot; for it is sealed:
12 And the book is delivered to him that is not learned, saying, Read this, I pray thee: and he saith, I am not learned. -Isaiah 29:11 - 12
These 2 verses are alluding to the Book of Mormon. When Joseph Smith recieved the plates he had a 4th grade education, and knew absolutly nothing about ancient languages. Despite this, with the help and gift of God, he was able to translate the plates. Martin Harris, who was acting as scribe, wanted to show some of the characters and their translation to show to famus linguists. Joseph copied down several of the characters found on the plates, along with the translation (they were from a portion they had already translated).
Martin traveled to New York and met with Dr. Charles Anthon, who was considered THE guy for translation of anything ancient in the early 1800's (this visit occured in 1828). After examining the characters and the accompanying translation, Dr. Anthon stated that they were authentic and that the translation was correct.
On his way out, Dr. Anthon asked Mr. Harris where Joseph had gotten the plates in the first place, and Mr. Harris told him the story of Moroni's visits. Anthon then asked for the certificate back, and tore it up in front of Martin. He told Martin that he was the victim of fraud and that he should bring the plates to him. Martin explained that he couldn't because they were sealed. Dr. Charles Anthon's response was thus-
"I can not read a sealed book."
In summary. a sealed book was delivered by an angel to an unlearned man, who was able to read and translate it for all the world. When a learned man tried to read, he could not, stating that he couldn't read a sealed book.
This prophecey of Isaiah was fulfilled in February 1828.