In an evening talk, Dogen said:
"Even people in the secular world must concentrate on one thing and learn it thoroughly enough to be able to do it in front of others rather than learn many things at the same time, without truly accomplishing any of them.
"This holds all the more true for the buddha-dharma, which transcends the secular world, and has never been learned or practiced from the beginningless beginning. We are still unfamiliar with it. Also, our capacity is poor. If we try to learn many things about this lofty and boundless buddha-dharma, we will not attain even one thing. Even if we devote ourselves to only one thing, because of our inferior capacity and nature, it will be difficult to clarify buddha-dharma thoroughly in one lifetime. Students, concentrate on one thing."
Ejo asked, "If so, what thing or what practice should we choose to devote ourselves to among the various ways of practice of the buddha-dharma?"
Dogen replied, "It depends upon one's character or capability, however, up to now, it is zazen which has been handed down and concentrated on in the communities of the patriarchs. This practice is suitable for all people and can be practiced by those of superior, mediocre, or inferior capabilities. When I was in China, in the assembly of my late master Tendo Nyojo, I sat zazen day and night after I heard this truth. When it was extremely hot or cold, monks there stopped sitting for a while because they were afraid of getting sick. At the time, I thought to myself, 'I may become sick and die. Still, I should just practice zazen. What is the use of clinging to this body? How can I refrain from practice when I am not sick? Dying from illness because of practice accords with my original wish. First of all, I am fortunate to be able to practice and die in an assembly under a good teacher in great China, and to be buried by such great people with an authentic Buddhist funeral. If I were in Japan, it would be impossible to have a funeral service performed by such people according to the Buddhist rituals. If I were to die during practice before clarifying enlightenment, I would be born into the family of Buddha again because of having established the relationship. It is meaningless to live long without practicing. It is useless. Furthermore, even if I wished to keep my body secure and healthy, I might drown in the ocean or meet an accidental death; how regrettable it would be!'
"With such resolve, I continually sat upright day and night. Yet I never once got sick. Now, each of you should practice exclusively and wholeheartedly. Ten out of ten of you will attain the Way. My late master Tendo encouraged us in this way."