2 Chronicles 20:14-15 Then the Spirit of the Lord came on Jahaziel son of Zechariah, the son of Benaiah, the son of Jeiel, the son of Mattaniah, a Levite and descendant of Asaph, as he stood in the assembly. He said: “Listen, King Jehoshaphat and all who live in Judah and Jerusalem! This is what the Lord says to you: ‘Do not be afraid or discouraged because of this vast army. For the battle is not yours, but God’s.
The bible tells us that God does nothing without revealing to his servants, the prophet. Amos 3:7 Surely the Sovereign Lord does nothing without revealing his plan to his servants the prophets.