妙法蓮華經玄義 8.43

8.43

As for the mind containing a bubbling spring: the mind is replete with all dharmas, but because of obstructions they do not flow, just as earth and stones press upon a spring, but removing the blockage makes it surge and flow forth. If one does not contemplate the mind, the mind is dark and unillumined, and what one expounds does not develop. If one contemplates the mind clearly and thoroughly, then one's eloquence is boundless, overflowing and inexhaustible; is this not a bubbling spring of speech? If one does not contemplate the mind, practice has interruptions; by virtue of contemplating the mind, thought after thought continues uninterruptedly, transforming the six hindrances into the six perfections, and the six perfections gather in all practices. This is the bubbling spring of practice. If one can contemplate the mind, it is like using a sharp mattock to dig into the ground: through bedrock and salty sand, the water of principle is clear and pure, surging without exhaustion. This is the bubbling spring of meaning.