Why does it mention Efrayim?
Rashi: [They needed salvation] in the war with Aram, when they besieged Shomron, and [the king] sent messengers to Achav "Kaspecha u'Zhavcha Li Hu v'Nashecha u'Vanecha ha'Tovim Li Hem" (Melachim I, 20:3).
Malbim: Refer to 80:3:3:2.
Why does it mention Menasheh?
Rashi: In the days of Yo'ash ben Yeho'achaz, Hashem saw their affliction "Ki Ibdam Melech Aram va'Ysimem ke'Afar Ladush" (Melachim II, 13:7). Yo'ash struck them three times and returned Arei Yisrael (ibid., 25).
Malbim: Refer to 80:3:3:2.
Why does it mention Binyamin?
Rashi: In the days of Mordechai and Esther, they were in danger, and the entire generation depended on them.
Malbim: (a) Arouse Your Gevurah that You showed in earlier days in front of Efrayim, Menasheh and Binyamin. (b) Many from Efrayim and Menasheh came to Chizkiyah (Divrei ha'Yamim II, 15:9). Nebuchadnetzar's Galus included Yehudah, Binyamin (who were with Yehudah), Efrayim and Menasheh. The verse mentions Efrayim, Menasheh and Binyamin, because they are from Bnei Yosef 1 , and they will stand against Bnei Esav - "v'Hayah Beis Yakov Esh u'Veis Yosef Lehavah u'Veis Esav l'Kash" (Ovadyah 1:18).
Binyamin is not from Bnei Yosef! Perhaps there is an omission. It should say that Esav will fall only to the seed of Rachel (Midrash ha'Gadol Ki Setzei 25:18). Binyamin is the foe of Esav, and apt to defeat him, for he is the only son of Yakov who did not bow to Esav (Chomas Anach Emor 1). (PF)
Why does it say "Orerah Es Gevurasecha [u'Lechah li'Yshu'asah Lanu]"?
Rashi: When they need salvation, even if they are Resha'im and are not worthy, arouse Your Gevurah for them, for salvation is to You. It is proper, and also upon You, to save both liable and worthy, like You told Moshe "Ra'o Ra'isi Es Oni Ami" (Shemos 3:7). The double expression of seeing hints that I see that they will anger me - even so, I saw their affliction [and I will save them], due to the Shevu'ah that I made to Avraham.
Why does it say "u'Lechah li'Yshu'asah Lanu"?
Rashi: "U'Lechah" is not an expression of Halichah (going), rather, like Lecha (to You). So it says in Mesorah, together with "u'Lechah Efo" of Yitzchak (Bereishis 27:37), "u'Lechah Ein Besorah Motzeis" (Shmuel II, 18:22) and "Simlah Lecha Katzin Tihyeh Lanu" (Yeshayah 3:6).
Radak: Go in front of us, and save us!
