A novice meditator attempts to still the river-like thoughts in their mind, while a true master of meditation stands by the river, observing the flowing water, their heart unmoved, unattached, and unburdened by the current. 

The seabed is motionless as the waves roll endlessly on the surface of the sea. The waves are like the endless manifestations of this world, but if your consciousness can be as steady as the seabed, all the surface waves will have no effect on you. You can even influence the fluctuations of the waves.