I have been puzzling that one (the prayer) since it ws posted earlier. I looked it up and it is dated 1784 so clearly isn't a new oddity. However, I think it falls into one of 3 categories ... it's a prayer and so, like poems and songs, is afforded a different level of grammatic expectation ... it's quite old and, has already been pointed out, language changes over time ... it says 'lay me down' as opposed to 'lay down' so isn't quite the same meaning.
Or am I looking too deeply into this