The interpretation by Redhorse is one Roy Acuff took from the song by Rev. Guy Smith, but see the posting by Joe Offer. Here he quotes the original Bible passage, and the original meaning seems to be the church.
Stewie, I may be wrong (can't help it not having all the data) but I thought all of the verses in version #2 (in DT) were actually used by Smith in his published poem before Acuff recorded it. I also have notes that Acuff's original recording had only four of the verses. He varied it through the years.
I think Joe is closer to the biblical meaning (his training and background). Neither Acuff (or myself) have the theological background to get at the true meaning.