首楞嚴義疏注經 9.26

9.26

Drawing in and holding limitless pure light to express verbal explanation is called "the substance of teaching." This light expressing verbalization is free from all coarseness and heaviness, hence it is said, "emitting pure transformations." Manifesting instructions according with capacities with complete clarity, it is said, "its responsive applications are inexhaustible." Because the stage of the second dhyāna lacks the first five consciousnesses, they merely use radiance for verbal expression; using light as sound, it is called the Heaven of Radiant Sound.