The fact that
Jacob wrestled with the man all night with neither gaining an
advantage over the other suggests that the man was his
equal in size, strength, and endurance. When
the book says, "And he said, Let me go, for the day breaketh," it is at first
unclear which man is speaking, Jacob or the stranger. As
Igloowhite pointed out, the passage says nothing about the man being an angel until he renames Jacob
Israel. Many
biblical commentators have taken this to mean that Jacob was wrestling (
metaphorically, perhaps) with
himself and his own ideas about
G-d.
This is significant (to me, at least) because the Jews are known as b'nai yisrael, or the Children of Israel, the man who struggled with G-d. They are not the Children of Abraham, who had everything figured out and believed in G-d to the point where he would sacrifice his own son for Him. They are the children of the man who wrestled with his internal misgivings all night and did not even conquer them, but walked away wounded. What I take from that is that we are not supposed to accept G-d blindly, but instead to argue and struggle with Him and with ourselves, perhaps for all of our lives, even if we do not get a clear answer.