SHYLOCK AS A BAD JEW
To see the full scale of Shylock's offense against his faith, we must here distinguish an oath to execute justice, with justice broadly and universally understood, from an oath to take private revenge. In the former case, the call to mercy would insist that the rigor of justice be tempered with mercy. In the latter case, precisely because private revenge is less morally defensible than other understandings of justice (e.g., deterrence, correction, or public retribution), the call to mercy is that much stronger.
By resisting mercy for the sake of private revenge, Shylock places himself at a very great distance from the Divine commandment to be merciful. Shylock compounds his misuse of the Divine when he later says “By my soul I swear” that no words can persuade him not to seek revenge (IV.i.239).
Shylock directly refers to God and the Devil on one occasion each. In response to Tubal's account of Antonio's bad luck, Shylock says, “I thank God, I thank God!” (III.i.96). Shylock refers to the Devil to insult Antonio (IV.i.344).
Shylock takes two actions that indicate his use of religion for personal gain: He breaks kosher out of hatred toward Christians and to make it more likely that Antonio will default (II.v.11–15),and he instructs Tubal to meet him at their synagogue with an officer (III.i.118–23). Shylock uses his house of worship to arrange his revenge.
By contrast with Launcelot, Shylock gives us a purely secular proverb. And he does so in the service of gain.
These examples demonstrate that Shylock's hypocrisy before Tubal is a consistent part of his character. In Shylock's hands, religion becomes a tool for private ends rather than a means by which God is glorified and His word obeyed. Throughout the play, there is no reference by Shylock to the Jewish faith or its elements that does not in some way relate either to his own suffering or to his desire for gain or revenge.
Shylock inverts the appropriate relationship between God and man. He elevates himself above Judaism. But this should not be taken to mean that Shylock is an insincere Jew. Shakespeare gives us no indication that Shylock is an unbeliever. Shylock is an example, not of disbelief, but of warped belief. He is a man who mistakenly places himself at the center of his religious beliefs and who lacks the self-knowledge to know what he is doing. Neither his religion nor his money has benefited Shylock; indeed, they have harmed both him and others. Both money and religion serve his greed and his desire for revenge.
At the end of the play, Antonio has stripped him of his religion and a good deal of his money (IV.i.379–89). Scholars have noted that this makes him into a wounded and therefore more sympathetic figure. At the same time, the forced conversion is bound to be interpreted as an insult to Judaism. We might suspect, though, that Shakespeare is comfortable having Shylock's religion taken from him, not because he believes that Jews need to be rescued from the Old Law but rather, because over the course of the play Shylock has demonstrated that in his specific case, his use of his religion, like his use of his money, does both him and others more harm than good.