"Measure for Measure" takes its title from the Gospel according to Matthew: "with what measure ye mete, it shall be measured to you again" (Matthew 7:2), a passage from the Sermon on the Mount. This sermon emphasizes the difference between outer sanctity and inner corruption, between seeming and being. Like the play, the Sermon on the Mount stresses the world of the soul, the intentions, the mind: emphasizing not only on what a person does but also what he thinks, the inner life is even more significant than the outer life.
The law as figured in the Ten Commandments can speak to behavior, distinguishing between what is good and what is bad; but it cannot speak to attitude and intention. Moreover, in its specificity, the law is prone to become concrete legalism, a pharisaical focus on the letter of the commandment, a process that allows individuals to focus on the details of the law rather than the intention of the law to create holy people. That is why Lucio talks about the sanctimonious pirate that went to sea with the Ten Commandments, but scraped one out of the table (Act I, Scene II).
"Measure for Measure" concerns itself with human behavior, to be sure. It considers the need for statutes, laws to govern human appetites and ensure domestic tranquillity. But it also focuses our attention on the inner world, that aspect of the individual which functions according to values and which may be called the moral center of the person.
The congruence between outer actions and inner values is one of the overriding themes of the play, especially as it is manifest in the issue of seeming and being. The Duke himself notes the difference between appearance and reality as he speaks about his deputy Angelo, who appears to be the perfect deputy and the disciplined (even puritanical) character (Act I, Scene I). Noting Angelo's character, the Duke also questions the integrity of his inner and outer worlds: Lord Angelo is precise; sta...