1)
Why did He say "Lo Osif"? Had he exiled them before?
1.
Radak: When they sinned, He made enemies rule over them, and they exiled them from their land, even though there was not a total exile before David.
2)
Where did He promise not to exile them?
1.
Malbim: "V'Samti Makom l'Ami Yisrael
3)
Why does it say both "Kol Asher Tzivisi" and "ul'Chol ha'Torah Asher Tzivah Osam Moshe Avdi"?