What is "Tzor Te'udah"?
Rashi: This is part of the above Nevu'ah "Ki Cho Amar Hashem Elai" (11). Te'udah is an expression of warning, like "Ha'idosi Vachem ha'Yom" (Devarim 4:26).
Rashi, from Bereishis Rabah 42:3: This refers to Achaz. He Achaz (held, i.e. closed) Batei Kenesiyos and Batei Midrash, lest children learn from their Rebbi. He said, if there are no young goats (Talmidim), there will be no adult goats (Chachamim). If there is no flock, there is no shepherd. I will cause Him to remove His Shechinah! The Navi told him, all that you seal the Torah, so it will not be found in Yisrael, will not help you.
Radak: "Tzor", with the grammatical form of "Sov", refers to tying - "va'Tihyenah Tzeruros" (Shmuel II, 20:3), "u'Mevuka'im u'Metzorarim" (Yehoshua 9:4). Tzor and Chasom are Makor (like infinitives). The Navi says, all I need to do is wrap and seal the Torah with my Limudai (refer to 8:16:2:3).
Radak, based on Targum Yonasan: Hashem speaks. Tzor and Chasom are commands. Tzor is like Netzor - guard My testimony.
Malbim: Tzayer Wrap this warning (he was command to draw on the parchment figures of people plundering - refer to 8:1:3:3).
What is the meaning of "Chasom Torah b'Limudai"?
Rashi: [Tie My warning and seal the Torah on the heart of] those who learn Me - your Talmidim and those who fear Shamayim, who are called Limudei Hashem. Keshirah (tying) applies to learning Torah - "Kashrem Al Libecha Samid" (Mishlei 6:21).
Refer to 8:16:1:2.
Radak: They are Talmidim. Only they should see Torah; others do not want to see or hear Divrei Torah. If they hear them and do not fulfill them, their punishment is multiplied after being warned. "Limudai" is a To'ar (descriptive title) for Talmidim. It says "v'Chol Banayich Limudei Hashem" (54:12), "Limud Midbar" (Yirmeyah 2:24).
Malbim: They are Zecharyah and Uriyah (who were designated to be witnesses - verse 2). They will sign on the Torah.