This book opens with an incomplete acrostic psalm, as it only gets to the letter Kaph. However, this opening letter Aleph is very clear. Yahweh was a jealous, avenging, and wrathful God. He took out his vengeance and raged against his adversaries and enemies. However, Yahweh was slow to anger, but he was very powerful. Thus, he would not clear the guilty ones very easily.
Babylon was like a golden cup of God’s wrath. The various nations drank this wrath from this golden cup. Thus they got drunk and went mad. Now suddenly Babylon has fallen and fell into many pieces. You can cry for her. You can try to heal her wounds, in hopes that she would be healed. Everyone tried to heal Babylon, but nothing worked. Then Yahweh said that you could cry and wail for her. Nevertheless, everyone should go to their own country. The judgment against Babylon has reached to the high heavens. Yahweh has enacted his vengeance and vindication. They were now to return to Zion, Jerusalem, to declare the works of Yahweh, their God. Bye-bye Babylon!
As the people return from Babylon to Jerusalem, Zion, they are happy that God had brought his vengeance against the Babylonians. After all, the Babylonians had destroyed their Temple. Now the vengeance of Yahweh was destroying the Babylonian temples.