Why does it say "Oh Yachazek b'Ma'uzi"?
Sanhedrin 99b: This refers to one who learns Torah Lishmah (purely in order to understand it). Refer to 27:5:2:1*.
Rashi: "Oh" is like Im (if), like we find "Oh Noda Ki Shor Nagach Hu" (Shemos 21:36). If My nation would hold onto My strength, and not seek another strength, then "Ya'aseh Shalom Li."
Radak: This is engaging in Torah, the Ma'oz (strength) of the world.
Malbim: "Mi" in verse 4 applies also to this. One who will hold My Ma'oz and make Shalom for Me [I will not do evil to him].
Why does it say that this makes Shalom for Hashem?
Sanhedrin 99b: One who learns Torah Lishmah creates Shalom 1 in the Pamalia above and the Pamalia below.
Rashi: It would settle My Da'as and anger, which rings inside Me, that I do not avenge My afflicters. I would have Shalom with Midas ha'Din, which says 'how are these different than these?'
Radak: A time will come when Yisrael will make Shalom with Me.
Kli Paz: If they would engage in Torah strongly and l'Shem Shamayim, surely the attribute of Shalom, which is beloved above and below, would force Me to make Shalom with Yisrael.
Birkas Tziyon (ha'Gaon Ben Tziyon Aba Sha'ul) 1:27: R. Y. C. Zonenfeld expounded, the Gematriya of "Tziyon b'Mishpat Tipadeh" (1:27) is 1076, like "Talmud Yerushalmi" - this is its merit to be redeemed. It is Shalom and pleasantness (it is not full of challenges). The Gematriya of "v'Shaveha bi'Tzdakah" (ibid.) is 524, like 'Talmud Bavli', which is full of debate and challenges, which increase Torah ("Yachazek b'Ma'uzi"); in its merit, the exiles will return.
Why does it add "Shalom Ya'aseh Li"?
Radak: The repetition is to strengthen the matter.
