The lyrics in parenthesis are pretty clearly based off of Stonewall Jackson's dying words. The rest of the lyrics seem to be original.

You can listen to the song here on Spotify

If I had to bet on the song's meaning, my first guess is that it's really a tribute to fallen soldiers using Jackson's famous deathbed prose. Though I briefly thought it could have a veiled message re the Civil War, I decided that the second to last stanza wouldn't fit that message