What does it mean that the book is sealed in Isaiah?

In Isaiah 29, the sealed book symbolizes the spiritual blindness and ignorance of the people who are caught up in their own religious traditions without recognizing Christ. The passage highlights that both the learned and unlearned cannot comprehend the truth revealed in God's Word, as they lack the spiritual insight provided by the Holy Spirit. This sealing is a form of judgment for those who refuse to acknowledge the truth of salvation through Christ. It underscores the necessity of divine intervention in revealing Himself, as only Christ can unseal the book and impart true understanding to believers looking for salvation in Him.