Thanks for sharing Murphy's recording, Pappy Fiddle, it's a good one. Your explanation is also perceptive, though I would be wary of saying there are "no more miracles" -- just a minor nitpick.

Joe, I don't believe Ball himself wrote the song. Here's an example of the text from a 1920 religious book: The Heavenly Gateway: Jubilee Songs composed by Rev. Richard T. Trent. Though included in the book, several songs around it include the subtext "composed by" Rev. Trent, while this one does not. It was sung by Rev. N. L. Martin during the hours leading up to his death in 1917 (Church of God Evangel 1917-01-20: Vol 8 Iss 3)

The song was also attested to in the Frank C. Brown collection, under the title "William Shackleford's Farewell Song," collected 1920 by Southgate Jones of Durham, NC (link).

So perhaps Trent wrote the song, but perhaps not -- it's hard to say for certain. Though one reference predates his printing (and the other matches its age), it wasn't uncommon for folk preachers to sing songs for years before publishing them commercially, if at all. Though he was a songwriter, Estil would have been 7 at the time of this publication, or 4 at the time of its first reference I found.