I want to say a little more about Master Dogen's Vow. And I'm going to skip over the second paragraph for right now and go to the third one, because the third paragraph helps me understand the second one. The third paragraph goes --
Buddhas and Ancestors of old were as we.
In the future, we shall be Buddhas and Ancestors.
Revering Buddhas and Ancestors, we are one Buddha and one Ancestor.
Awakening Bodhi-mind, we are one Bodhi-mind.
As they extend their compassion freely to us,
we are able to realize Buddhahood and let go of the realization.
"Know that in this way there are myriads of forms and hundreds of grasses throughout the entire earth, and yet each grass and each form itself is the entire earth. The study of this is the beginning of practice. When you are at this place, there is just one grass, there is just one form; there is understanding of form and no-understanding of form; there is understanding of grass and no-understanding of grass. Since there is nothing but just this moment, the time-being is all the time there is. Grass-being, form-being are both time.
"Each moment is all being, is the entire world. Reflect now whether any being or any world is left out of the present moment."
In other words, all of time is present in every moment. All beings and all worlds are present in every moment. The Buddhas and Ancestors of old are in this moment. We as Buddhas and Ancestors of the future are in this moment. Future Buddhas and Ancestors are in this moment. We are one Buddha and one Ancestor.
In Zen, often we're told to focus on the present moment. "Present moment" can get to be a real fetish. But even as we focus on the present moment we may still be clinging to an idea of "present moment" that leaves things out. Can you focus but not cling?
Understanding "present moment" in this way illustrates, among other things, why it's a mistake for westerners to be in a big rush to sever ties with the Asian traditions. If you're shoving the Asian ancestors out of your western "present moment," you're missing the present moment.
Reflecting on the Buddhas and Ancestors can be useful if you are feeling discouraged. You might meditate with the words of Master Dogen's Vow. Feel the strength and compassion of Buddhas and Ancestors within you, within the present moment, and let it radiate out to all beings who are struggling and discouraged.