The Torah in Parashat Vayishlach tells the mysterious story of Yaakov's nighttime wrestle with an assailant as he makes his way towards Canaan, where he would reunite with his brother Esav. By the end of the narrative it becomes clear that Yaakov's assailant is angelic, rather than human, as Yaakov demands from him a blessing and he renames Yaakov "Yisrael," a name-change that is confirmed by God later in the parasha (35:10).
The Rashbam advances a particularly novel and unconventional reading of this incident, claiming that God dispatched the angel in order to prevent Yaakov from escaping from Esav. According to the Rashbam, Yaakov's nighttime crossing of the Yabok stream, which took place just prior to the assault (32:23), was intended as a secret escape route. The Rashbam refers us in this context to the verses in Sefer Shemuel II (17:21-24), which tell of King David crossing the Jordan River during the night to escape from the rebel forces led by his son Avshalom. Nighttime river-crossings thus appear to be associated with escape routes, and the Rashbam claims that here, too, Yaakov attempted to avoid his confrontation with Esav by escaping.
God, however, who had promised to protect Yaakov and return him safely to Canaan, wanted to ensure that Yaakov would reunite with Esav and emerge safely from this confrontation, which would confirm the truth of the divine promise. He therefore sent an angel to delay Yaakov until dawn, at which point Yaakov would be no longer able to make an inconspicuous escape. For this reason, once morning arrived the angel wished to take leave of Yaakov ("shalecheni ki ala ha-shachar" – 32:27); now that Yaakov could no longer escape along a secret route under the protection of the nighttime darkness, the angel's mission has been accomplished.
This approach of the Rashbam seems difficult to accept for a number of reasons, primarily, perhaps, because of its implications with regard to the name "Yisrael." The angel confers this title upon Yaakov because "sarita im elohim ve-im anashim va-tukhal' – "you have struggled against angels and men and have prevailed" (32:29) – presumably referring to Yaakov's triumph over the angel. According to the Rashbam's understanding of this episode, however, it is doubtful whether this triumph should be seen in a favorable light.
As Professor Nechama Leibowitz noted, it emerges according to the Rashbam's approach that Yaakov's "victory over the angel implies that his weakness, his wish to flee from the Lord, his natural physical fears triumphed over his faith and trust." In the Rashbam's view, Yaakov's confrontation with the angel was necessitated as a result of his unjustified fear of his brother; this is hardly one of the great, heroic moments in Yaakov's life. It seems very difficult to imagine that the name by which his progeny is forever known – Yisrael – serves to commemorate a moment of spiritual weakness, an event in which Yaakov failed to display the confidence and trust in God's promise that we would expect from our great patriarch.
For this and other reasons, Professor Leibowitz expresses her strong preference for the traditional reading of this verse, as Rashi cites from the Midrash, that Yaakov's assailant was Esav's representative angel, and this incident alludes to the fact that Yaakov and his descendants will always emerge triumphant from their harsh confrontations against the hostile enemies that rise against them.