A Further Indication Of The Heresy In Which The Godless Men Were Involved (Jude 1:8-10).
Jude now describes in a threefold way the folly of the ‘ungodly persons', and points out that their attitude conflicts with the known realities. They defile themselves by sin, they set God (or the Devil) at nought, and they speak contrary to things that even angels do not dare to get involved with.
He then cites an example from the apocalyptic work the Assumption of Moses, (but without citing it as Scripture), in order to demonstrate how careful even Michael the Archangel was in dealing with the Devil. We can compare how Paul similarly cites heathen philosophers in the same way without accepting all that they teach (Acts 17:23; Acts 17:28). He gleans the truth out of them.