What is Buddha-mind?

Question: What is Buddha-mind?

Answer: Your mind is it. When you see the selfsame essence of it, you can call it suchness. When you see the changeless nature of it, you can call it dharmakaya. It does not belong to anything; therefore, it is called emancipation. It works easily and freely, never being disturbed by others; therefore, it is called the true path. It was not born and, therefore, it is not going to perish, so it is called nirvana.

Bodhidharma, Fragmentary Notes of Bodhidharma’s Disciples