Blood and Humanity

In the Merchant of Venice, the Prince of Morocco's “And let us make incision for your love To prove whose blood is reddest, his or mine,” introduces the theme of superficial differences masking intrinsic similarities, the most intrinsic being that we share a common humanity. It foreshadows Shylock's “If you prick us, do we not bleed” speech. Both use blood as the metaphor of common humanity.