摩訶止觀 4.122

4.122

技術者，未得聖道，不得修通，虛妄之法，障於般若。般若如虛空，無戲論，無文字；若得般若，如得如意珠。但一心修，何遽怱怱用神通為？

As for skilled arts and techniques: before one has attained the noble path, one cannot practice supernormal powers. False and deceptive dharmas obstruct prajñā. Prajñā is like empty space, without conceptual elaboration, without words. If one attains prajñā, it is like obtaining a wish-fulfilling jewel. One should just practice with single-mindedness; why precipitously and rashly use supernormal powers?