This day of mourning will follow the destruction of Babylon the great, a mighty commercial and political center which "shall be utterly burned with fire" because "her sins have reached unto heaven" (Revelation 18:8, 5).
And what are those sins? And is "Babylon the Great" a literal city, the capital city of the empire of the beast in the last days? Or is it a metaphor depicting the wickedness of all such cities throughout the ages? Perhaps it is both!
In any case, this Babylon harbors many forms of wickedness hated by God--fornications, sorceries, bloodshed, etc. But the chief characteristic of its wickedness is its devotion to commercialism above all else. "The merchants of the earth are waxed rich through the abundance of her delicacies" (Revelation 18:3).
Note especially the burden of the mournful cry "no man buyeth their merchandise any more," for these weeping-and-wailing shipmasters and other captains of industry had been "made rich by her" (Revelation 18:15) but suddenly it will all be gone.
And note that merchandise! Not only "gold and silver" but also "slaves, and souls of men." In the last days when this awful judgment falls, these merchants will still be trading in "slaves, and souls of men."
Sad to say, involuntary slavery was really not abolished by Wilberforce, or Lincoln, or even Martin Luther King! It is still thriving today, especially in certain Muslim and other non-Christian strongholds. But it will end when Christ returns and then all His redeemed followers will gladly "serve him" forever (Revelation 22:3). HMM http://www.icr.org/article/5991/