Expositor's Bible Commentary Commentary Jude 1:10

"But these rail at whatsoever things they know not: and what they understand naturally, like the creatures without reason, in these things are they destroyed." — Jude 1:10 (ASV)

“Yet these men” connotes contempt. They, unlike Michael, presume to speak evil against what they know nothing about (cf. v.19, where Jude explains that they do not have the Spirit). These “dreamers” do have knowledge, but only on the instinctual level of animal passion. So like “unreasoning animals,” they are destroyed (by God) through the things they practice.