What is the significance of "va'Yatzmach"?
Radak: Until Tzidkiyah rebelled, he succeeded and grew quickly. His rebellion was in the Tamid year of his reign. In his fourth year he went to Bavel, like it says at the end of Sefer Yirmeyah, to greet Melech Bavel. When Nebuchadnetzar made him king, he authorized him over the kings around him - or Edom, Mo'av, Amon, Tzor and Tzidon 1 . They sent messengers to Tzidkiyah.
It says in Yirmeyah (27:3) that Yirmeyah sent to these kings that they should submit to Melech Bavel. I did not see there that Tzidkiyah ruled over them. (PF)
What is "Sorachas"?
Rashi: This is like "v'Serach ha'Odef" (Shemos 26:12; excess). Radak - the seed became a big vine. [Yehudah] is compared to a vine, and not to a cedar, like initially, because the kingship dwindled from when Menasheh became king. Initially it was like a cedar; which is higher than all trees. The vine is thinner and weaker than all trees.
Malbim: Its height spreads on the ground; it does not grow up. "V'Es Eilei ha'Aretz Lakach" (13:13) - to be a lowly kingdom and not get haughty. He took only the Giborim, so [the remnant] will not be a mighty cedar, just a vine that bears fruits, and is not strong. I.e. they will pay taxes to him, and not be strong in his kingship. Rather, he will be subservient and submissive.
Why is it called "Shiflas Komah"?
Rashi: He must serve Melech Bavel.
Radak: Even though Melech Bavel aggrandized Tzidkiyah, he wanted him to be lowly in front of him, and not be haughty over him, like the Mashal teaches, to be a lowly kingdom.
Malbim: The cedar branch used to be tall. Now it is a low vine!
What do we learn from "Lifnos Daliyosav Elav"?
Rashi: Daliyosav are its branches.
Radak: A vine, which is low, does not raise its branches. Rather, they turn to the vine. So Nebuchadnetzar wanted that they will serve Tzidkiyah and [Tzidkiyah] will turn to him like a slave to his master.
Malbim: Daliyosav are branches that go high; they will be lowered and turn to Tzaftzefah.
To whom do "Elav" and "Tachtav" apply?
Rashi: To Melech Bavel.
What is the significance of "v'Sharashav Tachyav Yihyu"?
Radak: The vine will not spread its roots far. Rather, they will be under the vine, in its place, near it. Daliyosav are a Mashal for bribery and service; the roots are a Mashal for kingship. In order that he will fulfill this, he made a Bris with him and imposed on him a Shevu'ah in Hashem's name.
Malbim: Also the roots will be bent under him - "Lishmor Es Briso Le'amdah" (17:14).
Why does it say v'Sharashav (masculine)? In this Parashah, usually Gefen is feminine!
Radak: We find that sometimes it is masculine - "Gefen Bokek Yisrael" (Hoshe'a 10:1).
Why does it say "va'Tehi l'Gefen"?
Radak: This is like v'Hayis l'Gefen (you will be a vine).
Malbim: The branch grafted onto Tzaftzefah sprouted, and became a vine. It used to be a mighty cedar! It was a vine by itself, not grafted, until it sent out Badim (a thick strong branch close to the root).
What are "Badim"?
Rashi: They are Motos 1 .
The verse says that the vine produced them! Presumably, Rashi means that they are thick branches proper to make staves from them. (PF)
What is the meaning of "va'Teshalach Pore'os"?
Rashi: It grew many branches.
Malbim: These are branches that yield fruits. I.e. Tzidkiyah was strengthened in his kingship.
It is written with Reish before the Aleph, and we pronounce it with Aleph after the Reish!
Radak: The Kesiv is big branches; the pronunciation is [small] branches that exude from them.
Why does it mention growing branches, but not fruits?
Radak: [Branches represent that] Tzidkiyah ruled over the kings around him, and they heeded him, as long as he guarded his Shevu'ah. It does not mention fruits, for his sons did not survive; they were slaughtered.