Thoughts by Dogen:
Hsüan-sha said: "I now know that you are living freely in the black mountain cave of demons." Take note, that from antiquity on, neither the sun nor the moon has replaced the other. The sun arises together with the sun; the moon arises together with the moon.
[...] For this reason, this luminous pearl, equated with the thusness of existence or the beginning of non-existence, is elusive. The world of all the ten directions in one luminous pearl: it is not said to be two or three. [...] it is a circle in descent, rolling down and down. Now that the luminous pearl's virtues are realized in this way, there are [the bodhisattvas] Avalokitesvara and Maitreya who at this moment see forms and hear sounds, and there are old buddhas and new buddhas who expound the Dharma through their manifested bodies....
Therefore, although its surface, turning and not turning, appears to keep changing, it is none other than the luminous pearl. To know that such has been the case is, itself, the luminous pearl. It has the sounds and forms which are heard [and seen] in this manner. Because you have already attained this, even though you may be so perplexed as to think you are not the luminous pearl, your perplexities and doubts, as well as various contrivances which you accept or reject, are all merely brief, petty thoughts. In other words, they are nothing but [the luminous pearl] making itself look like petty thoughts.
How then can we fail to care for it? The luminous pearl is infinitely brilliant. Every glitter of its color, every ray of its light, is the working of the world in the ten directions. Who can snatch it away from us? [...] Even if we are perplexed and worried, it does not mean that we are not the luminous pearl, nor that [perplexities and worries] are activities and thoughts which are aroused by it. Therefore our advances and retreats within the 'black mountain cave of demons' are nothing but one luminous pearl.