Amos 3:7-8

Surely the Lord GOD does nothing Without revealing His secret plan [of the judgment to come] To His servants the prophets. [Rev 10:7] The lion has roared! Who will not fear? The Lord GOD has spoken [to the prophets]! Who can but prophesy? [Acts 4:20; 5:20, 29; 1 Cor 9:16]