John Gill Commentary Daniel 10:9

"Yet heard I the voice of his words; and when I heard the voice of his words, then was I fallen into a deep sleep on my face, with my face toward the ground." — Daniel 10:9 (ASV)

Yet heard I the voice of his words Though he was struck with so much awe, and his spirits so greatly depressed, and his body reduced to so low a condition; yet he was capable of attending to the voice, and of hearing the articulate sounds pronounced, and of understanding what was said:

and when I heard the voice of his words, then was I in a deep sleep on my face, and my face toward the ground; as soon as he heard his words, he fell upon his face to the ground, either in a way of worship and adoration, of prayer and supplication, as the Arabic version suggests; or through awe and reverence of the speaker, as well as through faintness of spirits; and these being quite exhausted, as it were, might be the reason of his falling into a deep sleep; unless it can be thought he was lulled into it, through the sweetness of the voice he had heard.