In the Book of Revelation, a mighty angel calls out with a loud voice like a roaring lion. At that time, there were seven thunders which seem similar to the seven seals and seven trumpets, all containing messages of judgment:
Revelation 10:4: "When the seven peals of thunder had spoken, I was about to write; and I heard a voice from heaven saying, 'Seal up the things which the seven peals of thunder have spoken and do not write them.'"
This appears to be the only instance where some of the message is to remain concealed. Something analogous occurred in the Book of Daniel where the prophet was told to refrain from writing certain words because they could not be recorded at that time:
Daniel 12:4: “But as for you, Daniel, conceal these words and seal up the book until the end of time; many will go back and forth, and knowledge will increase.”
Can we know why John was not allowed to reveal what he heard?