Charles Ellicott Commentary Isaiah 14:7

"The whole earth is at rest, [and] is quiet: they break forth into singing." — Isaiah 14:7 (ASV)

They break forth into singing ... — The phrase is noticeable as characteristic of Isaiah (Isaiah 44:23; Isaiah 49:13; Isaiah 52:9; Isaiah 54:1; Isaiah 55:12), and is not found elsewhere. The emancipated nations are represented as exulting in the unfamiliar peace that follows on the downfall of their oppressor.