At the beginning of meditation training thoughts will arrive one on top of another, uninterrupted, like a steep mountain waterfall. Gradually, as you perfect meditation, thoughts become like the water in a deep, narrow gorge, then a great river slowly winding its way down to the sea; finally the mind becomes like a still and placid ocean, ruffled by only the occasional ripple or wave.
Sogyal RinpocheJust as if you put your finger into water, it will get wet, and if you put it into fire, it will burn, so if you invest your mind in the wisdom mind of the Buddhas, it will transform into their wisdom nature.
Sogyal Rinpoche