Because the LORD hath spoiled Babylon, and destroyed out of her the great voice; when her waves do roar like great waters, a noise of their voice is uttered:
Because the Lord hath ... destroyed out of her the great voice - where once was the great din of a might city, there shall be the silence of death (Vatablus). Or, the "great voice" of the revellers (Jeremiah 51:38-39; Isaiah 22:2). Or, the voice of mighty boasting (Calvin). Compare Jeremiah 51:53.
When her waves do roar - "when" her calamities shall cause her to give forth a widely different "voice," even such a one as the waves give that lash the shores (Jeremiah 51:42). (Grotius.) Or "when" is connected thus: 'The great voice (in her), when her waves do roar like great waters' (cf. Jeremiah 51:13). Calvin translates, 'their waves' - i:e., the Medes bursting on her as impetuous waves; so Jeremiah 51:42, "The sea is come up upon Babylon." But the parallel, a "great voice," belongs to her; therefore the wave-like "roar" of "their voice" ought also to belong to her, (cf. Jeremiah 51:54). The "great voice" of commercial din, boasting, and feasting, is "destroyed;" but in its stead there is the wave-like roar of her voice in her "destruction" (Jeremiah 51:54).