"Fill a cup to its brim and it is easily spilled...."
This is phrase from the Tao, and of course it can be applied to many things. In martial arts, I see this as learning too much at once (and retaining little). Or, memorizing many techniques but not understanding the basics. Three strong basic movements can be much more valuable to a student than 100 misunderstood ones.
"Temper a sword to its hardest and it is easily broken..."
This line goes with the previous one. To me, in budo, this would include over-training to the point of exhaustion/injury. It could also mirror the previous statement in that so many finely detailed techniques could be easily toppled by a strong foundation.
"Gravity is the source of lightness, Calm, the master of haste..."
Again, a stable base allows for flow and fluidity. This can reflect physical balance, too, in stance-work and execution. And of course, when the mind is settled, one's movements, thoughtlessly, will arrive faster and more effectively.
"To reduce someone's influence, first expand it..."
This concept may be thought of as a tool in the defensive arts such as allowing an attacker to build confidence--throw an attack--and allowing them to leave him/herself vulnerable to a counter move. Giving the opponent room in order to take it back on your own terms.
"The river carves out the valley by flowing beneath it. Thereby the river is the master of the valley..."
This one reminds me of two things. One, is when I've watched my Sensei spar against taller opponents--he bends himself even lower until the opponent is unknowingly bending as well--then Sensei quickly stands upright, now equal in height to the taller opponent, and then nails them. The other thought, of course, is the intrinsic value of letting go of ego in budo.
This last one needs no comments:
"Compassion is the finest weapon and best defence. If you would establish harmony, Compassion must surround you like a fortress. Therefore, a good soldier does not inspire fear; A good fighter does not display aggression; A good conqueror does not engage in battle; A good leader does not exercise authority. This is the value of unimportance; This is how to win the cooperation of others; This to how to build the same harmony that is in nature."