It appears to me that 2 Peter 2:1-11 could be structured as follows:
1 Now there were also false prophets among the people, just as there will be false teachers among you. They will secretly introduce destructive heresies, even denying the Master who bought them—bringing swift destruction on themselves. 2 Many will follow in their depravity, and because of them the way of truth will be defamed. 3 In their greed, these false teachers will exploit you with deceptive words. The longstanding verdict against them remains in force, and their destruction does not sleep.
- 4 For if God did not spare the angels when they sinned, but cast them deep into hell,a placing them in chains of darkness to be held for judgment; [but saved loyal angels as per Rev 12:7-9 - see appendix below.]
- 5 if He did not spare the ancient world when He brought the flood on its ungodly people, but preserved Noah, a preacher of righteousness, among the eight;
- 6 if He condemned the cities of Sodom and Gomorrah to destruction, reducing them to ashes as an example of what is coming on the ungodly; 7 and if He rescued Lot, a righteous man distressed by the depraved conduct of the lawless 8 (for that righteous man, living among them day after day, was tormented in his righteous soul by the lawless deeds he saw and heard)—
9 if all this is so, then the Lord knows how to rescue the godly from trials and to hold the unrighteous for punishment on the day of judgment.
10 Such punishment is specially reserved for those who indulge the corrupt desires of the flesh and despise authority. Bold and self-willed, they are unafraid to slander glorious beings. 11 Yet not even angels, though greater in strength and power, dare to bring such slanderous charges against them before the Lord.
It appears that Peter brings three pieces of evidence to prove his contention that God can destroy the wicked while saving the righteous. Let me put this in more stark relief by use of a table:
||Loyal angels (as per Rev 12:7-9)
||Noah and family
|Sodom and Gomorrah
||Lot and daughters
APPENDIX - The Devil Cast Out
Note the comments of Albert Barnes on Rev 12:9.
And the great dragon was cast out - See the notes on Revelation 12:3.
That there may be an allusion in the language here to what actually
occurred in some far distant period of the past, when Satan was
ejected from heaven, there can be no reason to doubt. Our Saviour
seems to refer to such an event in the language which he uses when he
says Luke 10:18, "I beheld Satan as lightning fall from heaven"; and
Jude, perhaps Revelation 12:6, may refer to the same event. All that
we know on the subject leads us to suppose that at some time there was
a revolt among the angels, and that the rebellious part were cast out
of heaven, for an allusion to this is not infrequent in the
Scriptures. Still the event here referred to is a symbolical
representation of what could occur at a later period, when the church
would be about to spread and he triumphant, and when Satan would wage
a deadly war against it. That opposition would be as if he made war on
Michael the archangel, and the heavenly hosts, and his failure would
be as great as if he were vanquished and cast out of heaven.