Yeah, I originally had a longer post there, but then worried I was adding too much.
As far as I can tell, Isaiah is foreseeing the results of the coming of YHWH for an earthly reign in the Messianic age, what we’d call the Millennium Reign. That’s pre-resurrection. The “abhorrence” comes from survivors of Jerusalem being sent out in groups over the next several months to gather and bury the remains of the army (Syrian if I recall correctly!) that had been staging a siege on Jerusalem and was about to over-run it when Christ touched down on the Mount of Olives outside the city and proceeded to nuke the invading army (inspiring surviving soldiers from Judah to charge out and help a little, too).
The survivors go out in squads to shovel the dead bodies into a mass grave, mainly a trench many miles long extending from Gehenna Valley north toward Tar Meggido (Armageddon) where the invading soldiers were staging their siege (and possibly through a split in Olivet Hill caused when Christ touches down there). They also pick up firewood and other fuel to help burn the bodies, as well as for their personal needs for years afterward, during this time.
However, this isn’t meant entirely as a disgrace to the enemy. Once the mass bodies are buried in the Gehenna extension, groups are still sent out for a long time to scout for left-over corpses and even for bone pieces, marking them for proper burial in Gehenna later – the idea apparently being that they should be buried with the same hope of resurrection as the Jews themselves in principle want! Other prophets talk about this situation in much more detail, and I don’t recall offhand where, but Winchester (the Baptist universalistic evangelist from the days of the Revolutionary War and the early Napoleonic period) does in detail in his lectures on prophecies yet to be fulfilled. He tied the details together impressively enough for me to currently favor this theory (even though some of his other attempts are not so great and turned out to be patently wrong, to be fairly critical of his efforts).
It’s possible something similar (on this theory) is intended for the even larger army which masses in Edom (led by the ten kings or their survivors, expected to be the largest army ever assembled) for assaulting the Messiah soon afterward, which He goes out personally to slaughter hand to hand (rather than nuking them from a distance as during His arrival), leading to the Edom area’s ruin. Eventually the area recovers (and the people YHWH wounds/kills there will be eventually healed!), but before it has fully recovered a highway is made through it for pilgrims coming to Jerusalem, and they’re astonished and revolted and terrified at the destruction.
That’s my take on it. It may have been fulfilled in a superficial way at Jerusalem in 70 (although you should be able to see some hugely important and different differences, to say the least – starting with Jerusalem being saved from invading besiegers by YHWH’s personal direct intervention instead of wiped out by the Romans! (And again a generation later.)) But the details point to a very different kind of fulfillment that hasn’t happened yet.
And Jesus takes that fulfillment (as well as the oncoming 70 disaster for Jerusalem) to stand as examples of coming judgment for everyone.
