Jude 8-10
Jude has just laid out three lessons from three groups in history.

1) Israel,

2) certain fallen angels, and

3) Sodom and Gomorrah. Each followed their own desires, rebelled against the good authority of God in a key way, abandoned their assigned positions, and each experienced severe and pointed divine judgment. With that as the lens, Jude now focuses the fierce light of exposure on the foundation and source of the actions of false teachers.