A wise general makes a point of foraging of the enemy.
If you know neither the enemy nor yourself, you will succumb in every battle
One who sets the entire army in motion to chase an advantage will not attain it.
Management of many is the same as management of few. It is a matter of organization.
When the leader is morally weak and his discipline not strict, when his instructions and guidance are not enlightened, when there are no consistent rules, neighboring rulers will take advantage of this.
With regard to narrow passes, if you can occupy them first, let them be strongly garrisoned and await the advent of the enemy.