What do we learn from "v'Amech Kulam Tzadikim [l'Olam Yirshu Aretz]"?
Sanhedrin 98a: Mashi'ach can come only in a totally worthy generation [or a totally unworthy generation - refer to 48:11:1:1].
Radak: Kel will refine them - " u'Tzrraftim ki'Tzrof Es ha'Kesef" (Zecharyah 13:9) . All who remain will be Tzadikim - "v'Hayah ha'Nish'ar b'Tziyon veha'Nosar bi'Yrushalayim Kadosh Ye'amer Lo" (above, 4:3).
Malbim: This is why "vi'Yrechech Lo Ye'asef" (20, i.e. the Tzadikim). Do not say that there will not be Tzadikim among you - "v'Amech Kulam Tzadikim." Also refer to 60:21:2:2.
What do we learn from "l'Olam Yirshu Aretz"?
Radak: They will never be exiled from their land again.
Malbim: Do not say that the 'moon' will cease, for they will be exiled - "l'Olam Yirshu Aretz."
Why they called "Netzer Mata'ai Ma'asei Yadai"?
Radak: It will be seen from their deeds that I planted them - unlike initially, "va'Ykiv La'asos Anavim va'Ya'as Be'ushim" (5:2). They did not look like what Hashem planted, rather, like a foreign vine branch.
Malbim: Do not say that the nation will be sparse, weak and flimsy - "I planted it, My deed to glorify in them."
What is "Lehispa'er"?
Rashi: I will glorify Myself in them. Radak - they will be called Am Hashem - "Yisrael Asher Becha Espa'er" (49:3).
