Is a trumpet blown in a city, and the people are not afraid? Does disaster come to a city, unless the LORD has done it?
He adds, in the last place, Shall a trumpet sound and the people tremble not? Here he reprehends, as I have said, the torpidity of the people, to whom all threatening were a sport: “When a trumpet sounds,” he says, “all tremble; for it is a signal of danger. All then either fly for aid or stand amazed, when the trumpet sounds.
The scope of these verses is to convince the people of Israel that God had a controversy with them. That which the prophet has to say to them is to let them know that the Lord has something to say against them, Amo 3:1.
Commenting on Amos 3:1-8
Surely the Lord God will do nothing,.... In the world, in a nation or city; no remarkable event has happened, or shall happen, to the sons of men: but he revealeth his secret unto his servants the prophets; what he willed and determined to do, which was a secret in his own breast, till revealed; and this generally, and for the most part, he makes...