Antonio is very nave regarding the terms of the bond, making a dangerous and hasty decision. He takes the "pound of flesh- clause as a show of friendship and not hatred: "The Hebrew will turn Christian: he grows kind- (Act I, scene iii). Perhaps he received the terms of the bond in this manner because he is confident that he will be able to pay back the loan. Shylock feels completely justified in exacting revenge upon Antonio because he blames him for all his problems and is bitter about the manner in which Antonio has treated him in the past. He is, to say the least, bitter and disgusted at the torture and ridicule that Jews have experienced, at the hands of the Christians. Through the bond he feels he will be able to avenge the treatment of his kind: "to bait fish withal: if it will feed nothing else, it will feed my revenge the villainy you teach me I will execute, and it shall go hard but I will better the instruction- (Act III, scene i). He says that he will lead by the example of the Christians, showing that he is no better than they are, although he complains about their behavior towards him.
It is during the trial scene and the scenes immediately preceding it that Shylock's irrational and obsessive hatred for Antonio becomes apparent. He appears to be openly aggressive, warning those who have treated him like "a dog- to "beware my fangs."" This is emphasized greatly by the contrast between his and Antonio's behavior. Antonio realizes that Shylock will not reason with him and finally gives up: "Let him alone: I'll follow him no more with bootless prayer- (Act III, scene iii). Legally and technically, Shylock is right. It is not stated in the law that he should be merciful if the debt is not repaid, but perhaps morally he should be obliged to practice it, as Portia explains to him at length. His ruthless pursuit of revenge on Antonio exposes him as an extremely callous and evil man.
