Lankavatara Sutra Chapter 2, Section XLIII

As usual I'm using this translation.

Mahāmati asks the Buddha about where does he pronounce sound to be eternal, and the response begins with the notion that our taking this world as "what it is" is fraught with distortion.

As much of the text in subsequent sections is a variety of ways of re-telling and positing the "not one, not two or more" nature of non-duality, I'm going to skip the text until about section LII, and pick it up later there.