6.19

"One who is able to adapt to the enemy and obtain victory is called 'divine.' Thus, of the five phases, none is constantly victorious. Of the four seasons, none hold a constant position. The day is short or long; the moon is dead or alive."
- Sun Tzu

In this final passage of Book 6, Sun Tzu links the army's ability to be "like water" and adapt to the enemy with Heaven, calling this ability "divine." Such an ability is considered "divine" because it adheres to the same principle that governs the movement of celestial bodies (like the sun and the moon) and the effect this movement has on us (i.e. in the form of the seasons).

Sun Tzu's point, though poetic, is clear: because it imitates the changing nature of nature itself, an army that is responsive to its enemy, adapts to its enemy's movements, appears natural - as natural as the passing of the seasons, the changing length of days, the waxing and waning of the moon. This effect is powerful because it makes it difficult for the enemy to know what the army is planning.

In life, you must take heed of this understanding. Taking a formless position makes your actions appear natural and mysterious to others. Just as it is difficult to comprehend why nature operates the way it does, people will find it difficult to understand why you are acting the way you are acting. Being unable to comprehend your actions, you will have an advantage in making any competitive moves.