Genesis 32:26

And he said, Let me go: he saith this, partly to show the prevailing power of his prayer with God, and partly to quicken and encourage Jacob to persist in his conflict. Compare Exodus 32:10 Deuteronomy 9:14. The day breaketh, and I am not willing that there should be any spectators or witnesses of these things. Except thou bless me with the blessings which thou hast promised to Abraham and to me, among which one is protection in this hour of my danger. For Jacob now began to think that it was no man, nor ordinary angel, that was with him, but God himself, as he saith, Genesis 32:30.