John Gill, on Jer 51:8

Babylon is suddenly fallen and destroyed,.... Or "broken" (g); even into shivers, as a cup is; for when it had been used to answer the purposes designed by the Lord, he let it fall cut of his hands at once, and it was broken; or rather he dashed it in pieces, as a potter's vessel. The destruction of Babylon was brought about in a very short time, considering the strength of it; and was unexpected by the inhabitants of it, and by the nations round about; but, when it was come, it was irreparable: so the destruction of mystical Babylon will be in one hour, and it will be an utter and entire destruction, Rev 18:8; howl for her; as the inhabitants of Babylon, and her friends and allies that loved her, did no doubt; and as the kings and merchants of the earth, and others, will howl for spiritual Babylon, Rev 18:9; take balm for her pain, if so be she may be healed: or balsam; see Jer 46:11; which is said by way of derision and mockery, as Kimchi and Abarbinel observe; or in an ironical and sarcastic manner; suggesting, that, let what means soever be made use of, her wound was incurable, her ruin inevitable, and her case irrecoverable. (g) "confracta est", Schmidt; "fracta est", Cocceius; "contrita est", Piscator.