What does Jude 1:13 mean?

But these speak evil of whatever things they don’t know. They are destroyed in these things that they understand naturally, like the creatures without reason.

Woe to them! For they went in the way of Cain, and ran riotously in the error of Balaam for hire, and perished in Korah’s rebellion.

These 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 trees without fruit, twice dead, plucked up by the roots;

About these also Enoch, the seventh from Adam, prophesied, saying, “Behold, the Lord came with ten thousands of his holy ones,

to execute judgment on all, and to convict all the ungodly of all their works of ungodliness which they have done in an ungodly way, and of all the hard things which ungodly sinners have spoken against him.”

These are murmurers and complainers, walking after their lusts (and their mouth speaks proud things), showing respect of persons to gain advantage.