Dōgen, Shōbōgenzō [Treasury of the Eye of the True Dharma], Chapter 3: Buddha NatureThe Buddha said, “If you wish to know the meaning of the buddha nature, you should observe the conditions of the time. If the time arrives, the buddha nature appears.”
This “if you wish to know the meaning of the buddha nature” is not just about knowing: it means also “if you wish to practice it,” “if you wish to verify it,” “if you wish to preach it,” and “if you wish to forget it.” That preaching, practicing, verifying, forgetting, mistaking, and not mistaking are, all of them, “the conditions of the time.” In “observing the conditions of the time,” one observes using the conditions of the time; one mutually observes using the whisk, the staff, and so on. They cannot be observed using in addition the wisdoms of “contaminated wisdom,” “uncontaminated wisdom,” “original awakening,” “initial awakening,” “non-awakening,” “right awakening,” and the like.
[The meaning of] “should observe” has nothing to do with the observer or what is observed; it should not be guaged by such [notions] as right observation or false observation: it is “should observe.” Because it is “should observe,” it is not one’s own observing, it is not another’s observing. It is the very “conditions of the time” themselves; it transcends conditions. It is the very buddha nature itself; it is the buddha nature with body cast off. It is each buddha himself; it is each nature itself.
A bunch in the past and present have frequently thought the words “if the time arrives” mean that one awaits a time later when the buddha nature might appear. “Continuing to practice in this way,” they say, “one encounters the time when the buddha nature appears naturally; if the time does not arrive, even though one visits a teacher and asks about the dharma, even though one makes concentrated effort to pursue the way, it will not appear.” Taking such a view, they return in vain to “the red dust,” they stare vacantly at the milky way. Types like this are doubtless followers of the alien path of “the naturalists.”
What is called “if you wish to know the meaning of the buddha nature” is saying, for example, “you should know the meaning of the buddha nature.” To say “you should observe the conditions of the time” is to say “you should know the conditions of the time.” If you wish to know what is called “the buddha nature,” you should know it is precisely “the conditions of the time.” To say, “if the time arrives,” means “the time has already arrived; what is there to doubt?” Let doubting the time be as it may, “return the buddha nature to me.” We should realize that “if the time arrives” is “not passing the twelve times in vain.” “If it arrives” is like saying “it has arrived.” If it were “if the time arrives,” the buddha nature would not arrive; therefore, since the time has already arrived, this is the appearance of the buddha nature. Or “its principle is self evident.” In sum, there has never been a time when the time does not arrive, nor a buddha nature that does not appear.