Why does it say "v'Yatza Choter mi'Geza Yishai"?
Rashi: If you will say, there is consolation for Chizkiyah and his nation, that they will not fall in Sancheriv's hand, but what will be with those whom he exiled to Chalach and Chavor? Perhaps their hope is lost? It is not lost - in the end, Melech ha'Mashi'ach will come and redeem them 1 . "Choter" is a staff of kingship.
Radak: This Parshah about the days of Mashi'ach is put next to the promise in the days of Chizkiyah, so you should not be astounded at the wonder that Hashem will do to fell Machaneh Ashur in a moment. Hashem will do a greater wonder for Yisrael in the days of Mashi'ach when the exiles will be gathered. This will be from the family of Melech Chizkiyah. It mentions Yishai, for the first king came from him. It mentions Geza (the trunk) and Sharashav (its roots); when a tree is cut, it sends out shoots from its trunk and roots. The shoots come out from next to the trunk, and also from the roots under the ground. Because Yisrael were exiled from their land for many years, and their kingship ceased, it is as if the tree was cut, but the stump and roots remain. There is room for the trunk to regenerate.
Malbim: After describing the cutting of Sancheriv's camp, it says that a shoot will emerge from the stump of Yishai; it will be a great forest - "ha'Ba'im Yashresh Yakov Yatzitz u'Farach Yisrael" (27:6). The order of the verses shows that this Nevu'ah is about Chizkiyah. However, the promises were not fulfilled in his days! Really, it is about the end of days. Refer to 11:1:3:3.
Malbim: The time of Ge'ulah began with the exile in the days of Sancheriv. I.e. then the Nevi'im began prophesizing about the Ge'ulah from all ends of the world. The Ge'ulah in between from Bavel was only for Yehudah. There are two times for the Ge'ulah of the Klal - if we merit, "Achishenu" (Hashem will bring him early). If not, he will come "b'Itah" - the latest possible time (Sanhedrin 98a). The possibility for early redemption began in the days of Chizkiyah. This is the intent of Sanhedrin 94a - Hashem wanted to make Chizkiyah Mashi'ach, and Sancheriv would be Gog and Magog (refer to 9:6:2:1 and the notes there). Had they merited, all the prophecies for the future redemption would have been fulfilled then.
What is "Netzer"?
Rashi: It is an expression of a tree nurturing.
Malbim: Refer to 11:1:3:3.
Why does it say "v'Netzer mi'Sharashav Yifreh"?
Rashi: This Nevu'ah was to console those whom Ashur exiled.
Radak: Refer to 11:1:1:2.
Malbim: When a tree is cut and its stump is intact, it sprouts again from its stump. The stump slowly rises. Such growth is called Shoter; the branch that emerges from the stump is thick and strong. However, if the stump is cut, and only the roots remain in the ground and it sprouts from the roots, then the growth is not attributed to the first tree; it is like a new tree. The sprig that emerges from the root is soft and weak; it is called Netzer. Had they merited the general Ge'ulah in the days of Chizkiyah, it would have been from Geza Yishai , i.e. Malchus Beis David; Mashi'ach would be attributed to him. If not, much time will pass and the stump (Malchus Beis David) will be Batel. The root will remain, and a new growth will sprout from it.
