When we sit in a quiet forest when there’s no wind, the leaves are still. When the wind blows, the leaves flutter.
The mind is the same sort of thing as leaves. When it makes contact with an object, it vibrates in line with its nature. The less you know of the Dhamma, the more the mind vibrates. When it feels pleasure, it dies with the pleasure. When it feels pain, it dies with the pain. It keeps flowing on in this way.
– Ajahn Chah, Theravada, Thai Forest Tradition.