In an appendix to his edition of The Merchant of Venice (The New Cambridge Shakespeare) (pp. 197-8) , M. M. Mahood explores Shakespeare’s use of the Bible in the play. He notes the extensive echoes of the Jacob narrative, some explicit some not so much.

“Shakespeare is unlikely ever to have known an orthodox Jew, and any Marranos he may have met in London would have been at pains to conceal their religious origins. To get at these origins and so to endow Shylock with his pride of race, Shakespeare naturally went to the stories of the patriarchs told in the Book of Genesis. The Church Lectionary had already made him familiar with one of these stories, the account in Genesis 27 of the manner in which Jacob’s ’ wise mother wrought in his behalf so that he wrested his father’s blessing and inheritance from his brother Esau. But he pursued the narrative through succeeding chapters on his own initiative, and in doing so conceived Shylock’s imaginative involvement with Jacob : an aspect of the Jew which brings him to life just at the moment we are in danger of stereotyping him as the conventional stage usurer . . . .

“Jacob’s dealings with his brother and his long service with Laban offer Shylock the model for his own defiant enterprise in a hostile society, while the mysterious episodes of Jacob’s ladder and of the wrestling angel underlie Shylock’s deep sense of apartness, his Old Testament ‘righteousness’. Some commentators on the play have viewed the story of Laban’s sheep as a self-indictment on Shylock’s part, in that it is a defence of something manifestly wrong; but, as actors have always realised, the dramatic effect of Shylock’s identification with Jacob in this anecdote is to give him the vitality of the born survivor.”

That much is evident from Shylock’s use of Jacob to justify usury, but the use of the Jacob narrative spreads throughout the play: “Jacob’s exaction of a blessing from the blind Isaac is parodied, perhaps unconsciously, in Lancelot’s scene with Old Gobbo. In swearing by Jacob’s staff Shylock is made to recall Jacob’s boast in Genesis 32 that this was all he had in the world to begin with. Shylock’s wife bears the name of one of the two wives of Jacob who figure in Genesis 29-33. ‘Hagar’s offspring’, first heard of in Genesis 16, reappear in Genesis 28 when the granddaughter of Abraham’s bondmaid Hagar marries Esau, whose descendants are destined to serve those of Jacob. In such ways Shakespeare makes use of what was essentially a humanistic knowledge of the life of Jacob as related in Genesis, a knowledge no different in kind from his study of Plutarch’s Lives.”