Jude calls the intruders “hidden reefs” at the believers’ love feasts, describing them as dangers beneath the surface Jude 1:12. He adds images like “waterless clouds” and “fruitless trees” to stress their emptiness and harm Jude 1:12.
In Jude 1:12–16 Jude paints a string of sharp images to expose certain people as dangerous and empty. They blend into shared meals yet harm the community like unseen reefs. They look promising but deliver nothing, like waterless clouds and fruitless trees. Their behavior is restless and shameful, like violent waves and drifting stars headed for darkness. This unit sits inside Jude’s larger warning that some have slipped into the community and are corrupting it from within (earlier in the letter, Jude describes them and gives past examples of judgment).
Jude 1:12–16 presents certain insiders as both dangerous and empty. They participate in the community’s shared meals, but their presence is like an unseen hazard that can wreck others.
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with Jude 1:12, then read the surrounding section so the answer stays connected to the passage's flow.
12These are hidden rocky reefs in your love feasts when they feast with you, shepherds who without fear feed themselves; clouds without water, carried along by winds; autumn leaves without fruit, twice dead, plucked up by the roots;