1. Portia asks Shylock to show mercy upon Antonio and spare his life. She acknowledges that Shylock does have a right to "his pound of flesh," but that a merciful person would either forgive the debt or settle for something "less invasive."
2. In Portia's "Quality of Mercy" speech, she argues that mercy should apply infinitely to all situations. She cites examples of a merciful God and attempts to make an ethical appeal to Shylock's religious beliefs. While Portia's speech would be motivating to most audiences, she neglects to consider that Shylock does not believe in the merciful God of the New Testament. He trusts in the vengeful, omnipotent God of the Old Testament. Likewise, throughout the play, Shylock references Biblical characters who did not hesitate to get their dues (i.e., Jacob).
Portia also misunderstands the motivation behind Shylock's strange sentence. She does not consider the fact that Shylock desires revenge upon Antonio because never once did Antonio show mercy toward Shylock.
Overall, Portia's poetic speech about mercy's qualities is more in keeping with the flowery language of Belmont but is ineffective in Venice's business environment.