Tenzin Palmo, a nun in the Tibetan tradition wrote:
There is the thought, and then there is the knowing of the thought.
And the difference between being aware of the thought and just thinking is immense.
Normally we are so identified with our thoughts and emotions, that we are them. We are the happiness, we are the anger, we are the fear. We have to learn to step back and know our thoughts and emotions are just thoughts and emotions. They’re just mental states. They’re not solid, they’re transparent.