I always saw this song listed in Kingston Trio collections, but I didn't grow up with it, as any son of my mother and 60s coffeehouse folksinger might be expected to have been. There is also a good Johnny Cash version, but I like this one best.
It captures Appalachian sentiments on a coupla three levels. First, it looks like it is about one simple, actually oversimple idea, that it takes a strong man to turn the other cheek; but upon further review there is the almost hidden but devastating complexity of including the idea that having "to walk that lonesome valley by yourself" is enough to stop an angry, powerful man in his tracks. And it is. The Reverend Mr. Black fells the lumberjack with one sung sentence, and when we run it over in our minds we realise it is true. Whatever pain and anger you are bringing here son, the answer is not in hitting me, but in a personal journey you have not yet taken. We know immediately that most listeners won't pick up that meaning, being stuck on the first one. But it's there.
Secondly, there is the common theme of lonesomeness from the hills, which hovers in the background of a lot of Appalachian music and writing, ignored for decades until maybe the 30s and 40s and then noted for decades, once people got around to the idea that "Hey we should actually go up into the hills and ask these people what they are all about."
The region is from its inaccessibility a very secluded one. There are but few roads—most of them little better than mountain tracks—and practically no railroads. Indeed, so remote and shut off from outside influence were, until quite recently, these sequestered mountain valleys that the inhabitants have for a hundred years or more been completely isolated and cut off from all traffic with the rest of the world (Cecil Sharp)
The word “lonesome” plays a large role in many songs from this region, including “lonesome dove,” “lonesome day,” “lonesome night,” and “lonesome grave,” among others. In addition to loneliness, these songs often carry a melancholy sensibility and helpless fatalism in which the characters in the narrative are caught in events over which they have no agency or must live with the consequences of actions they have initiated. “Lonesome Valley” seems to be the most prominent usage in the “lonesome” family and somewhat iconic in its own right, even used as the title of a novel by Henry Hornsby, Lonesome Valley (New York, 1949)
They became celebrated and cool in the 60s and especially 70s, in the creation of bluegrass (a fairly modern amalgam of several old-time musics), the fascination with various "roots" musics, the Foxfire books, and the back-to-the-land ethos, so we now don't quite fathom how unknown this region was to most of America. After the wars many in the 50s moved down to find jobs in Cincinnati or Atlanta or Charlotte and even their own children only went back a few times. Its cultural distinctness was not a mere pose by the residents or an affectation by the hippie and folksinging visitors but a reality. David Hackett Fischer and Albion's Seed has a good summary of the founder effects, but the isolation was greater than it had been in Scotland and certainly Ireland for the simple reason that there was more land. Dirt-poor hillbillies in West Virginia had more land than lairds in Scotland. I believe that isolation was as powerful a force as the exodus from the siege of Londonderry because it lasted 200 years.
There are questions in the song. What in the world does this lumberjack have against this man, or preachers in general? We are not told. How can the Rev Black preach hellfire but let this man off the hook? It doesn't fit the theme. This is typical of the stripped-down lessons of the region, told in stories like parables. The horse, the admiration for a father, the idealisation of a man of the cloth - these are are all common decoration on the Appalachian tree. But they are mostly there for atmosphere, not quite part of the lesson.
If you want a slowed down portion of that core song "Jesus Walked That Lonesome Valley," here is a personal favorite, the Fairfield Four. They sang this in "Oh Brother Where Art Thou?"It should be noted that there was a mid-19th C African-American spiritual called "Down in the Lonesome Valley," though we have neither lyrics nor music for it. That could also be a source for the song that the Reverend Mr Black sings, if not the song about him. The categories that we make now for songs and their origins did not exist then. They were passed back and forth.