The Vision After the Sermon (Jacob Wrestles the Angel) 1888, is a striking and memorable painting by Gauguin. Having never studied the Old Testament, there are holes in my understanding of the imagery. Knowledge of such stories can add understanding and enjoyment to both ecclesiastical and secular works of art. However, getting to the bottom of why Jacob was wrestling with the angel highlights inconsistent interpretation of biblical text made more glaring by Google. Here's what we came up with, striving to not add further complication and acknowledging that this is only a veneer of a complicated subject:
Jacob was the twin brother of Esau, son to Isaac and Rebekah, and grandson to Abraham and Sarah. He was born second, clutching his brother's ankle (Jacob means "leg-puller"), with the prophecy that his elder brother would serve him. Through trickery Jacob obtains Esau's birthright and is forced to flee from his elder brother's wrath. After 20 years away and much prosperity, Jacob decides to return home to Canaan. Along the way he hears that his brother marches to meet him with 400 men. Jacob sends Esau gifts such as flocks of goats to preceed their meeting. At the ford of Jabbok, Jacob is left alone for the night and meets a man, (also described as an angel, God, or being) who wrestles with him until dawn. The being cannot best Jacob, but touches his thigh, leaving him limp for life. Jacob will still not release the angel until being blessed. After renaming him Israel (meaning "a prince with God"), the angel blesses him and departs without telling Jacob (now Israel) who he is. Israel names the spot Peniel meaning "the face of God".
Why does this supernatural being wrestle all night with a mortal when he could so easily beat him? Why are they fighting at all? Jacob is seeking the blessing of forgiveness from his brother. The long wrestling bout is a test of his dedication to this wish and could be seen as an analogy to a more internal mental struggle to do the right thing. He is marked by a limp and new name after the meeting with the angel, indicating that "seeing God" or following the right path will change your life irreparably.
This, of course, is loose talk. Here is the text from the King James version for your reference.
From Genesis, Chapter 32
24 And Jacob was left alone; and there wrestled a man with him until the breaking of the day.
25 And when he saw that he prevailed not against him, he touched the hollow of his thigh; and the hollow of Jacob's thigh was out of joint, as he wrestled with him.
26 And he said, Let me go, for the day breaketh. And he said, I will not let thee go, except thou bless me.
27 And he said unto him, What is thy name? And he said, Jacob.
28 And he said, Thy name shall be called no more Jacob, but Israel: for as a prince hast thou power with God and with men, and hast prevailed.
29 And Jacob asked him, and said, Tell me, I pray thee, thy name. And he said, Wherefore is it that thou dost ask after my name? And he blessed him there.
30 And Jacob called the name of the place Peniel: for I have seen God face to face, and my life is preserved.
31 And as he passed over Penuel the sun rose upon him, and he halted upon his thigh.