Why does the Torah refer to 'Machaneh' both in the feminine ("ha'Achas") and in the masculine ("v'Hikahu")?
Rashi: 'Machaneh' belongs to a group of words that are dual-gendered, such as Shemesh, Ru'ach and Eish. 1 Ha'amek Davar- it says ha'Achas (feminine) for the first, for it was weaker; if one will be stricken, it should be the weaker one.
See Rashi for examples in Tanach for each of these words.
What is the significance of Yaakov's statement, "then the remaining camp will escape"?
Rashi: Yaakov prepared himself for Esav's arrival in three stages 1 : (a) By sending him gifts; 2 (b) By praying 3 (as was his way) 4 and (c) by applying war strategy (in case Esav attacked), 5 as hinted here. Consequently, while Esav attacked the one camp, he (Yaakov) would take on Esav and the other camp would escape. 6
Ramban: While Esav was fighting the one camp, the other camp would be able to escape, either by fleeing, or because Esav's anger would abate and he would cease fighting or Hashem would intervene in some other way and save them.
Seforno: While Esav is busy taking the spoil from the one camp, the remaining camp will escape.
Ohr ha'Chayim: The camp that was ready and armed will surely save itself. Perhaps also the first camp will be able to save itself. Yaakov did all this to avoid needing a miracle.
Malbim: If Esav will strike the camp of his flocks and shepherds, the camp of his wives and children would escape.
The Midrash Rabah learns from here never to place all one's money in one corner (or to quote a well-known adage 'Never to put all one's eggs in one basket'), a lesson which Ovadyah took to heart, when he hid 100 Nevi'im from the wicked Izevel - 50 in one cave and 50 in another cave (Melachim I 18:4).
32:14-22.
32:10-13.
See also Ramban.
This is because Yaakov knew that, on no occasion, would all of his descendants fall into the hands of Esav; if the king of one country would issue harsh decrees against our bodies, the king of another country would offer us refuge.
QUESTIONS ON RASHI
Rashi writes: "The word 'Machaneh' can be either masculine or feminine." But why would the same word be treated as both masculine and feminine in the same verse?
Gur Aryeh: Regarding such items, 1 when referring to its fundamental aspect, the masculine is used, but when discussing a tangential aspect, the verse uses the feminine. In the word "v'Hika'hu" (m); Yaakov was afraid that Esav would strike the camp as a camp, i.e. and wipe it out.
Rashi writes: "The remaining camp will be spared - despite Esav; for I will fight against him." How do we know to interpret this way?
Gur Aryeh: Otherwise, how can Yaakov say with certainty that the other camp will be spared?
Rashi writes: "The remaining camp will be spared - despite Esav; for I will fight against him." But see the verse, "Should Aram overpower me, you will be my salvation" (Shmuel II 10:11); which ostensibly means, 'perhaps you will be able to save me.' Perhaps here too, Yaakov was merely hoping that they would somehow be saved?
Mizrachi: Chazal teach that Yaakov prepared for his encounter with Esav in three ways, one of which was preparing for battle. Rashi finds the source for this in this phrase; as he explains, 'they will be spared - for I will fight against him.' 1
Gur Aryeh: In Sefer Shmuel as well, Yoav was saying that certainly you will be able to help me in some degree (even if I am losing the battle). Here too, Yaakov was saying, 'certainly the other camp will be spared.'
Gur Aryeh - But Rashi already derived this in the preceding verse, "'He was troubled' - lest he kill others [i.e. in battle]" (Rashi to 32:8)?