In The Merchant of Venice, the audience is first introduced to Shylock in Act I, scene iii. Bassanio is negotiating with him for a loan which Antonio will take out on his behalf and which will allow Bassanio to woo Portia. Portia is a wealthy heiress from whom Bassanio believes he previously received "fair speechless messages" (I.i. 164), meaning that he thinks she is attracted to him. The audience senses a shrewd businessman in Shylock as he deliberates on the potential loan of three thousand ducats but is also aware almost immediately of his dislike of Antonio, foreshadowing what will follow.
When Antonio enters, Shylock verbally attacks Antonio and the audience is shocked at the intensity of his hatred. This makes the audience feel unsympathetic towards Shylock because his feelings do not seem justified. Shakespeare has cleverly painted a picture of a virtuous Antonio at this stage and the audience is unlikely to understand the implications of Shylock's words as it is offended and has no idea that Antonio has contributed to Shylock's complete mistrust and revulsion. The exchange between the two men is full of double meaning and the audience begins to see another side to Antonio as he patronizes Shylock and is indifferent to his claims. Antonio even admits that he will continue to "spit on thee" (I.iii.126) and, even though Shylock will lend him the money, Antonio asserts that he is still his "enemy" (130). Just as the audience begins to feel sorry for Shylock because of Antonio's treatment of him, Shylock delivers his blow. He adds a condition to the terms of the bond and, if Antonio cannot pay it back, he must allow for "an equal pound of your fair flesh, to be cut off..."(144-145). The audience now feels no sympathy for a man who jokes or makes demands in such severe terms.
The audience will continue to feel no compassion towards Shylock as he does not endear himself to anyone. Launcelot, Shylock's servant, will leave Shylock's house and Jessica, Shylock's daughter intends to run away with Lorenzo. However, there are brief moments when the audience realizes that he is a victim of circumstance and is perhaps hardened because of ill-treatment. As he says in Act III, scene i, " The villainy you teach me I will execute," (61) in which he means that he learns from Christians and puts that into practice. However, once again, it does not take Shylock long to reveal his worst side as he seems more concerned about his missing belongings than his daughter and rejoices in the apparent sinking of Antonio's ships. A brief show of regret is evident when Shylock learns that a ring that he received from his beloved Leah has been pawned. It's value to him is immeasurable and gives the audience a momentary insight into a Shylock who has long since disappeared.
After Portia's speech on "the quality of mercy" (Iv.i.179), the audience feels no sympathy for Shylock who relishes Antonio's certain fate. When Portia outwits him, still the audience is not compelled to feel sorry for him, especially when he tries to agree to the payment of the bond having just refused it in favor of Antonio's "pound of flesh" (302). However, when Antonio stands to profit from Shylock's unexpected misfortune, the audience is inclined to feel sorry for Shylock who always loses to Antonio and, this time, in a most merciless manner as he must renounce his religion in favor of Christianity. It seems that while Shylock learns a valuable lesson, Antonio will learn nothing.