Albert Barnes Commentary Daniel 8:18

"Now as he was speaking with me, I fell into a deep sleep with my face toward the ground; but he touched me, and set me upright." — Daniel 8:18 (ASV)

Now, as he was speaking with me, I was in a deep sleep on my face toward the ground - Overcome and prostrate with the vision. That is, he had sunk down stupefied or senseless. See (Daniel 10:9).

His strength had been entirely taken away by the vision. This is not improbable, as the sudden appearance of a celestial vision or a heavenly being can take away a person's strength. Compare (Genesis 15:12); (Job 4:13 and following); (Judges 6:22); (Judges 13:20, 22); (Isaiah 6:5); (Luke 1:12, 29); (Luke 2:9); (Acts 9:3, 8).

“But he touched me, and set me upright.” The marginal reading, which reflects the Hebrew, is “made me stand upon my standing.” He raised me up to my feet. So the Saviour addressed Saul of Tarsus, when he had been suddenly smitten to the earth by his appearing to him on the way to Damascus: “Rise, and stand upon thy feet,” and so on, (Acts 26:16).