Edom apparently took advantage of the defeat of Judah by playing the part of a thief who comes and helps himself to the substance of others when they can no longer defend themselves. They would never have done this in normal times, but like crows which attack a sheep stuck on its back, they watched carefully until they were sure there would be no resistance, and then they came.
That is exactly what happens with the godless, with those who reject the Lord and salvation, towards those who profess him and belong to him. Look at the way the people turned against Jesus Christ and detested him and hated him and cried out for his execution, little realising of course that he was suffering and dying on Calvary to take the punishment of our sins on our behalf. But they hated him and what he represented: that he was the Lord of glory, that he was the king of all the earth, and they couldn't stand that and so they were against him.
The same is seen in the history of the world. Sometimes, as at the present time in this country, the people of God, like Judah, are diminished and they fall upon hard times and the church seems to be small and nothing powerful, and then the forces of atheism gloat, and show how delighted they are, and they make every endeavour to intimidate, insult, disparage, smear the church of Jesus Christ and the message of God. But for all these things the world order will come into judgment showing her hatred of God by hatred of her representatives, her people and the language which is used is therefore very powerful.