This practice has been emphasized in the Mahayana tradition before spreading to Nepal and Tibet. It means that we steadily observe virtuous and non virtuous thoughts arising in the mind without desire or aversion, letting thoughts subside of their own accord and awareness arise without any object other than itself.
Chokyi Gyaltsen explained it this way:
“Whatever sort of thoughts arise, without suppressing them, recognize what they emerge from and what they dissolve into; stay focused while you observe their nature. By doing so , eventually the motion of thoughts ceases and there is stillness…each time you observe the nature of any thoughts that arise they will vanish by themselves, following which, a vacuity appears. Likewise, if you examine the mind when it remains without movement, you will see an unobscured, clear and vivid vacuity. That is called the union of stillness and motion”.
Dudjom Lingpa said;
“Eventually all coarse and subtle thoughts will be calmed in the empty expanse of the essential nature of your mind and consciousness comes to rest in its own natural, unmodified state. That experience is soothing, gentle, clear , limpid consciousness that is neither benefited nor harmed by thoughts, and you experience a remarkable sense of stillness without needing to modify, reject or embrace anything.”
Settling the mind in its natural state is an effective way of knowing the mind and healing the mind. We can remove mental habits by realizing :
That thinking the thoughts and images we experience don’t exist outside of our own mind,
That compulsively responding to mental events with craving and aversion are not intrinsically pleasant or unpleasant of themselves, we either make them pleasant or unpleasant
That we don’t need to identify with them as an independent agent who created them but just witness them in the space of our minds.
By observing our minds we get out of the rut of compulsively assuming that our thoughts and mental images of people and events accurately represent them as they exist independently of our own perspective and experience. They are just appearances. This is truly liberating! This brings contentment!