Albert Barnes Commentary Revelation 18:10

"standing afar off for the fear of her torment, saying, Woe, woe, the great city, Babylon, the strong city! for in one hour is thy judgment come." — Revelation 18:10 (ASV)

Standing afar off for the fear of her torment. Not daring to approach, to attempt to rescue and save her. Those who had so long contributed to the support of the Papal power, and who had in turn been upheld by that, would not now even attempt to rescue her, but would stand by and see her destroyed—unable to render relief.

Alas, alas, that great city Babylon. The language of lamentation that so great and so mighty a city should fall.

For in one hour is your judgment come. See the notes on Revelation 18:8.

The general sentiment here is that in the final ruin of Papal Rome, the kings and governments that had sustained her, and had been sustained by her, would see the source of their power taken away, but that they would not, or could not, attempt her rescue. There have been not a few indications already that this will ultimately occur, and that the Papal power will be left to fall, without any attempt on the part of those governments which have been so long in alliance with it to sustain or restore it.