1)
Why will they know "Ki Ani Hashem Elokeihem"?
1.
Malbim: They will recognize that also when I exiled them to the Goyim, I was "Hashem Elokeihem." It was not for evil, rather, for good and with My Hashgachah Pratis.
2)
What do we learn from "v'Chinastim Al Admasam"?
3)
What will Hashem not leave over?
1.
Rashi: He will not leave one of Yisrael in Galus.