All spiritual language originates in the actual experience of a real person, who then tries to convey that experience in words, using the poetic and allegorical options open to him. That’s why these writings are often prefaced by “It is as if….”
When this language decays over time, religion arises.
It is as if a cascade of tiny birds floods out from the open heart, illuminating the sky
It is as if after a short while these birds turn to stone and fall to the ground.
It is as if people gather up these birds, their shape and colour intact though lifeless and, fascinated, give them names: ‘Buddha nature,’ ‘No Mind.’
It is as if they collect all the birds lying there and put them together, to form structures.
It is as if each structure is a prison.