Rashi: This is said in astonishment. Malbim - did you not always disgrace Sedom?! This explains "Asher Pilalt la'Achosech" (52). You said all curses -'He who punished the people of Sedom should punish Ploni.' Sedom's shame was always heard in your mouth.

Radak: You did not verbally remember what you heard about the overturning of Sedom, because you were haughty. You did not say 'the end of pride is breakage. We should not be proud, for Sedom was overturned and broken due to its pride!'

Rashi: It is to rebuke many, and say 'do not be overturned like Sedom', as if this was a new tiding to you.

Rashi: When you were in your grandeur.

Radak: It is at the time of your serenity. This is plural, for Bnei Yehudah were proud about many things.