The Malach of Aisav is not allowed to leave until he blesses Yaakov.. He anticipates that Hashem will (in the future) change his name to Yisroel. He also gives him a Bracha.
Rashi, Chizkuni, RaDaK, Rabbeinu Bechayey, RaLbaG, Alshich , Chasam Sofer, Maamar (Alter Rebbe).
Why Yaakov must keep both names and not give up Yaakov for Yisroel (which the Malach may have wanted)
