Why does it say "Hashem Tzevakos"?
Radak (from Shemos Rabah 9:7): He heads legions above and below, i.e. Yisrael, who are called Tzevakos. Therefore, He did not want to eradicate all of us, like we deserved.
Why did Hashem leave a remnant for us?
Rashi: It was due to His mercy, and not due to our virtue.
Radak: It was due to His name, which is called on us.
Malbim: It was due to His Chesed.
How would we resemble Sedom?
Rashi: We would have been eradicated. Radak - we would be eradicated like Sedom and Amorah, because we 1 did like their deeds. The Kaf in Kim'at is to show the truth of the matter, like "Hishava Li ka'Yom" (Bereishis 25:33), "ka'Yom Timtze'un Oso" (Shmuel I, 9:13) and similar verses.
Malbim: Our deeds were like Sedom, which was worse than Amorah. Our Churban would have been like Amorah, from which no person escaped, unlike Sedom, from which Lot and his two daughters escaped.
Radak: The Navi said so; he included himself with the sinners, for the honor of Yisrael. Also Yirmeyah said "Nachnu Pashanu u'Marinu" (Eichah 3:42), and Hashem told Moshe "Ad Anah Me'antem Lishmor Mitzvosai Chukosai" (Shemos 16:28). Some say that Hashem intended also to rebuke Moshe. Refer to Shemos 16:28:1:2-3.
