When Dogen was in China he wrote this:

Break open a single particle and all the sutras grow clear:
the great merit-wheel of the dharma turns as a whole.
The womb of a donkey gives birth to the noble horse
Each time you look, you'll see it new.

Mysteriously, the skin-bag is the Buddha field. Even a failure, imperfect, raw, half-baked, crooked, call-it-whatever, everytime it will shine, both different and the same. This endless practice shows that impermanence is the body of Buddhas. Nothing you can do about it. If you want Heaven, Amida-land outside here and now, as it is, outside of the womb of this donkey...How can it be?