The Buddha Mind, unborn and marvelously illuminating, is like a bright mirror. A mirror reflects whatever is in front of it. It’s not deliberately trying to reflect things, but whatever comes before the mirror, its color and form are sure to appear. Likewise, when the object being reflected is removed, the mirror isn’t deliberately trying not to reflect it, but when it’s taken away it doesn’t appear in the mirror.
The Unborn Buddha Mind is just like this. It’s natural that you see and hear things, whatever they are, when you deliberately try to see and hear them; but when you see and hear things that you hadn’t originally anticipated seeing or hearing, it’s through the dynamic function of the Buddha Mind that every one of you has. That’s what’s meant by the Unborn Buddha Mind.
Zen master Bankei Yōtaku (1622-93)