"Practice without study leads to false arrogance. Without proper doctrinal study, we fall prey to the conceit that we are equal to the Buddha. It is likened to grasping a torch by the burning end. On the other hand, to restrict ourselves to doctrinal study, never getting authentic experience of our own "dharma treasure" is comparable to a pauper counting other people's money. Ideas 'enter our ears and exit from our mouths, yet the mind remains undisciplined', with the result that our opinions multiply, and once again we develop arrogance. Study of the teachings in the absence of practice is likened to grasping a knife by the blade." (From "Doctrine and Practice in Chih-i's Thought" by Neal Donner).
Nichiren occasionally quotes this passage.