Dogen Genjokoan Verse 11 (TA translation):
Accordingly, in the practice-enlightenment of the buddha way, to attain one thing is to penetrate one thing; to meet one practice is to sustain one practice.
Here is the place; here the way unfolds. The boundary of realization is not distinct, for the realization comes forth simultaneously with the mastery of buddha-dharma. Do not suppose that what you realize becomes your knowledge and is grasped by your intellect.
Although actualized immediately, the inconceivable may not be apparent. Its appearance is beyond your knowledge.