1)
Why does it say "v'Nashasti... Nasosh v'Abed"?
1.
Malbim: They will not be uprooted in order to be planted again, rather, in order to perish.
2)
How can it say that they will be lost? Below (46:27, 48:47, 49:6) it says that Hashem will return them!
1.
Radak #1: Those who learned Darchei Yisrael will return; the others will be lost.
2.
Radak #2: This is like R. Yehoshua said (Brachos 28a), they did not return yet 1 (just like Yisrael, even though it says "v'Shavti Es Shevus Ami Yisrael" (30:3). R. Gamliel argues.)
1
I.e. they will be lost until they learn; afterwards, they will return. (PF)
