Any fighter can tell you that the more you resist, the easier it will be for you opponent to take you. The harder I hold, the faster I lose energy. The more rigid I stand, the easier it is to take me off balance. The mark of a beginner is one who attempts to use strength and force to overcome their opponent. The more experienced practitioners would give a slight smile and teach the enthusiastic beginner that, although strength is important, how it's applied is more important still.
Bruce Lee famously advised us fighters to be like water since, "when you pour water in a cup, it becomes the cup....Water can drip and it can crash." Here, here!
There are some obvious meanings we can derive from his succinct analogy. I would contemplate, what does it mean to be shapeless and formless? Why would someone possessing tremendous will and fortitude not apply it forcefully when encountering foes?
I see many levels here. First the most apparent is that physical energy conservation and efficiency is crucial for the fighter. Anyone who's been in a fight knows that getting tired and losing steam is often the first step towards falling. To move with fluidity and to flow with the moment is the more efficient way to be in this kind of encounter.
But there is a deeper message here too. The fluid state is the receptive state. Becoming the cup that I am poured into, or, taking shape based on what the situation calls for, is responding to the moment. This means being open and receptive. This might sound counterintuitive for a fight, but if we look closer we might see how receptivity is the basis for all meaningful expressions of power. This is because it more closely reflects reality. We are not solidified, rigid things, but a constant iteration of being. A living process of evolution and transformation. Forceful movements cannot reflect reality, and therefore conflict with it. This conflict is what I call resistance, and it is the basis of all energy drain. Flowing with life, becoming the cup when in the cup, is the source of energy repletion.
To be receptive is to be fluid. To be fluid is to be in flow. To be in flow is to be ready to meet whatever arises.
This is a nice representation of a universal principle. When properly aligned, receptivity (feminine principle) directs the movement (masculine principle). This is true power, to remain in the receptive state as to be informed by the moment on what action to take. Even in a high stakes fight when a strategy has been prepared and rehearsed many times, if the fighter cannot make adjustments during the contest, their strategy could end up limiting them and causing their fall. Maybe you've heard someone say after losing a contest, "I beat myself". This is because they abandoned their receptivity and attempted to force the way.
As you have no doubt deduced, this line of contemplation can fit with nearly any circumstance in life. True power is to be at rest in the receptive state, and to take form as the need arises. Not to predict, not to resist, but to flow and improvise. There are times when preparation and rehearsal are quite important. But when it's time to perform, we must be ready for whatever arises so as not to be thrown off our game.