I laid me down and slept; literally, as for me, I laid me down, etc. A contrast seems intended between the king and some of his companions. "I, for my part," he says, "confident in God, calmly laid me down and slept; I did not allow the danger which I was in to interfere with my repose at night."
Others, probably, were less trustful. I awaked. When morning came, i.e; I awoke, as usual, from quiet and refreshing slumbers. For the Lord sustained me; rather, sustaineth me. Now and always I am sustained by the Almighty.