法界次第初門 3.66

3.66

Fifth, like an echo. 'Like an echo' means that in deep mountains, ravines, and valleys, or inside an empty, large building, whether it is the sound of speaking or the sound of striking, from one sound another sound arises; the unwise proclaim it to be the sound of someone speaking. The wise understand that this sound is produced by no one; it is simply due to acoustic resonance, and is therefore called an echo. The phenomenon of an echo is empty, yet it can deceive the ear faculty; all sounds and speech are also like this. When a person wishes to speak, wind comes out from the mouth, called udāna, and goes back down to the navel; when the sound comes out, it contacts seven places and turns back; this is called speech being like an echo. The unwise do not recognize the causes and conditions of speech; declaring it to be real, their minds grasp at it and give rise to sorrow and joy. The wise know that the causes and conditions of speech lack reality, like an echo; hearing it, their minds do not produce attachment. All dharmas are like this; therefore, it is said to be like an echo.