It is wise to be watchful of the movements of the enemy, and to safeguard oneself against them; and it is foolish to allow oneself to be watched, and to let the enemy safeguard himself against us. It is right to decrease the power of the enemy in every way possible, and to increase one's own power and make it much greater than the enemy's. It is right to know the secret of the enemy; and it is more than right to keep our secret from him.