These words have influenced me for more than 4 decades, “Be water, my friend“. In context, here is the specific passage.
Empty your mind.
Be formless, shapeless, like water.
You put water into a cup; it becomes the cup.
You put water into a teapot; it becomes the teapot.
You put water into a bottle; it becomes the bottle.
Now water can flow, or it can crash!
Be water, my friend.
– Bruce Lee