Surly the LORD God, will do nothing, but HE revealeth HIS secret unto HIS servants the prophets.
This is a powerful verse. The LORD is not a wizard, or puppet-master, pulling strings mindlessly. There is a purpose, and a plan.
In Part One of the King James we have B.C. - Before the Cross: where the LORD's prophets spoke of the unseen. The WORD came to them, and they repeated it.
In Part Two of the King James, the LORD'S prophets speak the WORD.
"His secret" is what is happening, with Understanding. It comes with warnings, and reward. Judgment can be good or bad.
Amos 3:6 "trumpet" - is actually shophar (Hebrew); a long horn, that was blown from high place.
The visual info is a "Seal" - before the event takes place. As things unfold, they become "signs" for us to see: as mile-markers along the highway.
A classic is Matt.24:3 the Disciples ask Immanuel-Christ-Jesus three questions. Christ explanation was in a "Seal." For us, it is a "Sign."
Much of the Prophecy in the Gospels, the Writings of Apostle Paul, and the Book of Revelation is about the Seals/Signs, Trumps, and Vials.
It is designed to be Understood by Followers: only!