Adam Clarke's Commentary on the Bible - 2 Peter 2:5
Spared not the old world - The apostle's argument is this: If God spared not the rebellious angels, nor the sinful antediluvians, nor the cities of Sodom and Gomorrha, he will not spare those wicked teachers who corrupt the pure doctrines of Christianity. Saved Noah the eighth - Some think that the words should be translated, Noah the eighth preacher of righteousness; but it seems most evident, from 1 Peter 3:20 , that eight persons are here meant, which were the whole that were saved... read more
Adam Clarke's Commentary on the Bible - 2 Peter 2:4
For if God spared not the angels - The angels were originally placed in a state of probation; some having fallen and some having stood proves this. How long that probation was to last to them, and what was the particular test of their fidelity, we know not; nor indeed do we know what was their sin; nor when nor how they fell. St. Jude says they kept not their first estate, but left their own habitation; which seems to indicate that they got discontented with their lot, and aspired to higher... read more