Charles Ellicott Commentary Isaiah 29:11

"And all vision 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:" — Isaiah 29:11 (ASV)

The vision of all ... —Better, the whole vision, i.e., the entire substance of Isaiah’s teaching. The words perhaps imply that this had been committed to writing, but that to the unbelievers they were as the roll of a sealed book. The same imagery meets us in Revelation 5:2.

The wise of this world treated its dark sayings as seals, which forbade their making any attempt to study it. The poorer unlearned class could plead a more genuine and less guilty ignorance, but the effect was the same with both.