I. Here is the war proclaimed (v. 1): Blow the trumpet in Zion, either to call the invading army together, and then the trumpet sounds a charge, or rather to give notice to Judah and Jerusalem of the approach of the judgment, that they might prepare to meet their God in the way of his judgments and might endeavor by prayers and tears, the church's best artillery, to put by the stroke. It was the priests' business to sound the trumpet (Num. x. 8), both as an appeal to God in the day of their distress and a summons to the people to come together to seek his face. Note, It is the work of ministers to give warning from the word of God of the fatal consequences of sin, and to reveal his wrath from heaven against the ungodliness and unrighteousness of men. And though it is not the privilege of Zion and Jerusalem to be exempted from the judgments of God, if they provoke him, yet it is their privilege to be warned of them, that they might make their peace with him. Even in the holy mountain the alarm must be sounded, and then it sounds most dreadful, Amos iii. 2. Now, shall a trumpet be blown in the city, in the holy city, and the people not be afraid? Surely they will. Amos iii. 6. Let all the inhabitants of the land tremble; they shall be made to tremble by the judgment itself; let them therefore tremble at the alarm of it.