Jacob's struggle with the angel is an open question-- the actual struggle, its results, and the blessing bestowed upon Jacob at its conclusion. The Midrash already raised the struggle to a metaphysical level. The man, for that is what the text actually says, ish, is an angel and according to one midrash he is "the guardian angel of Esau", according to another, "Samael, the guardian angel of Rome". Jacob is not merely Jacob the man, but a symbol of the struggle between the peoples of Esau - Edom and Jacob - Israel, or, if you will - Christianity vs. Judaism.
Most commentators follow Maimonides, saying that this act was a prophetic vision, not a real event. In his prophetic dream, Jacob saw himself grappling with the angel. So clear and tangible was Jacob's dream that, upon awakening, he felt the blow inflicted upon him by the angel that left him "limping on his hip" (Gen. 32:32). Rarely is a dream so lifelike that the dreamer awakens to see the effects of the dream on his body. Following are the attempts several commentators to grasp the significance of this event and invest it with a unique meaning.
R. Isaac Karo at the beginning of his commentary on the text says: "All that happens to the fathers is meant to happen to the sons, and all that happened to Abraham is a sign of the exile in Egypt, all that happened to Isaac is a sign of the Babylonian exile and all that happened to Jacob is a sign of our current exile... and indeed our exile is the worst, the most bitter, and the longest of them all ". In more detailed fashion, Karo returns us to Esau selling his birthright. Now Esau is demanding the return of two things Jacob took from him through guile: the birthright and the blessing. However, because of his evil acts he has no chance in such a confrontation with his brother. Therefore, he sends in his stead the "guardian angel of Esau" to grapple with Jacob. In this struggle, Jacob is the victor with regard to the blessing and the angel indeed does bless him, that is, he supports and reinforces the blessing. The name Jacob, deriving from aqov halev (Jer. 17:9) "contorted, deceitful", is changed to Israel, deriving from serara, authority, thus absolving Jacob of the deceit through which he originally obtained the blessing.
Yet in the matter of the birthright, Jacob does not come out on top and his defeat is symbolized by the blow to his hip. The Bible uses the term kaf hayarekh and Rabbi Karo wonders about the combination of these two words, kaf, meaning hand, and yarekh, meaning hip [actually, it refers to the hip socket, concave like the palm when cupped]. He therefore considers the word kaf as referring to Jacob's hand that grasped Esau's heel at the time of their birth. To demonstrate that no deceit was involved in the purchase of the birthright, Jacob sends Esau the gift offering in our parasha as further payment for the pot of lentils already paid for the birthright. Jacob is left limping because Esau has not yet received the gift, the payment.
Rabbi Eliezer Ashkenazi in his book Ma'ase Hashem also connects the struggle with the angel and the sale of the birthright. He says the story of the sale lacks many details and therefore it appears as if there had been a deception, but in fact a "document of sale" was legally signed between Jacob and Esau. So that the document would not get lost and would always be available for the purchaser, "the custom was that the person desiring to guard a document would strap it to his hip" (see also Baba Bathra 135b: "If a person died and a document was found strapped to his waist").
Jacob acted similarly with regard to Esau's document of sale. The angel strove to get at Jacob's hip to take the document away from him, thus nullifying the transaction, but was unsuccessful and the document remained in Jacob's care. Therefore, when blessing Jacob, the angel said: "for you have striven with beings divine and human, and have prevailed". According to Ashkenazi, this verse refers to the original struggle with Esau (= human) and to the current struggle with the angel of G-d (=divine), and to Jacob's victory in both instances. As in Karo's interpretation, the change of name indicates that the deal was not done through aqov, deceit, but by authority, serarah, as implied by the name Yisrael, which means it was done by law (Ma'ase Hashem, p. 118a).
Rabbi Isaac Abarbanel also thinks the struggle took place in the frame of a prophetic vision. We must distinguish between a prophetic dream and a prophetic vision on a very elevated level, what Abarbanel calls "a tangible prophetic vision". In such a vision, the prophet sees things in a most real way and performs tangible acts, such as, for instance, Abraham's actions during the visit of the three angels. He sees the statement that Jacob remained alone as a significant fact; if Jacob had only dreamt, there would be no meaning to his being alone, because the sleeper and the dreamer are always alone.
In this prophecy Jacob sees and senses the person struggling with him and tries to fell him, but fails to do so; instead, he injures his hip. The meaning of the vision is that the guardian of Esau, i.e. the nation, not the person, is trying to kill Israel, and there is a hint here of the continuing confrontation between the gentiles and Israel. In the prophetic vision, G-d tells Jacob that Esau will not be able to kill him. He will, however, strike Jacob's descendants, the fruit of his loins-the same word as "hip", in such a way that will not destroy them but will inflict pain and leave them limping. This situation will continue for as long as Jacob's descendants are in the land of Esau, i.e. in the Diaspora. But when the dawn shall break, when the Redemption comes, the gentiles will ask Jacob's descendants for permission to separate, and then the Jews will not allow them to leave - "I will not let you go unless you bless me" (Gen. 32:27). The significance of the blessing is the reaffirmation that Isaac indeed blessed Jacob and the acknowledgement that the blessings were received in good faith and not through guile.
Rabbi Shlomo Halevy, in one of the drashot in his book Divre Shelomo, explains this image in a similar manner. Unlike Abarbanel, R. Shelomo says that the vision was in a dream and it was intended to inform the Jewish people of future happenings. Esau's angel, Samael, has the upper hand only during the night - the period of exile, while the dawn brings with it redemption. The injury inflicted by the angel-Esau can only touch the descendants of Jacob when they are not worthy: "And behold the angel saw that rationally he could harm Jacob because of Jacob's wholesomeness, not to mention the merits of his father and mother and grandfather and grandmother... and so he smote his hip, meaning that he harmed Jacob's children (the fruit of his loins) who were rendered susceptible because of their lack of virtues". The gist of this explanation is that the people of Israel can be harmed by their enemies in times of mass conversion or when they are undeserving.
R. Shlomo lists three kinds of sins that lead to Esau overpowering the descendants of Jacob: 1. heretical beliefs and ideas; 2. bad deeds; 3. a split within the nation, even if each individual is virtuous on his own. After all, a limp occurs when the bones are not properly aligned and this symbolizes the lack of cohesiveness within the nation, arrogant behavior on the part of the young towards their elders, and people pushing their way into higher positions that they are not suited for. Rabbi Shlomo, like Abarbanel, interprets the blessing at the break of dawn as an affirmation of Isaac's blessing to Jacob (Divre Shelom 170a).