Jude 13 → Isaiah 57:20

Jude's depiction of false teachers as "wild waves of the sea, foaming up their own shame" (kymata agria thalassēs epaphrizonta tas heautōn aischynas) echoes Isaiah 57:20, where "the wicked are like the tossing sea, unable to rest, whose waters cast up mire and dirt" (yam nigrash ki hashqet lo yukal vayyigreshu memav refesh vatit). Both texts use the restless sea as a metaphor for the wicked — those who produce nothing but filth and refuse. Isaiah's context is a prophetic oracle distinguishing the peace God gives to the righteous (57:19) from the perpetual agitation of the wicked (57:20-21: "there is no peace for the wicked"). Jude applies this prophetic imagery to characterize false teachers as agents of chaos and moral pollution, whose activity produces shame rather than edification.