I heard a man of God say – only God could send a choir to bring down an enemy strong hold. Read Joshua 6
Can you imagine someone telling you that the only way to defeat the enemy is to demolish their battle lines with your voice?
Then the same God is consulted during a war and He tells David in 2 Samuel 5 that instead of attacking the enemy from the front, he should attack from behind them and the sound of marching it the branches of trees should be the sign that the victory is his.
Whistling within tree branches is normal? Marching???
David and Joshua must have been very trusting men