Angelo tells Escalus that they "must not make a scarecrow of the law" (II.i.1), meaning that they must not waver in their decisions. Escalus argues that they should "cut a little" rather than "fall, and bruise to death," comparing law enforcement to pruning a tree; it is better to trim the tree than to cut it down. He also brings up Claudio's specific case, asking Angelo to consider whether he could have erred in the same way at some point in his life.
Angelo responds, "Tis one thing to be tempted, Escalus, another thing to fall" (II.i.17). He argues that, despite the ever-changing line between lawmaker and criminal, the law must still stand firm. He admits that he himself is capable of transgression, but adds that he hopes to be treated with the same strictness should he do wrong. Angelo calls in the provost and tells him to ensure that Claudio is executed before nine o'clock the next morning.
Elbow enters, bringing Pompey and Froth with him. Angelo asks him what he is doing, and he replies that he is the Duke's constable, and that he has brought two "notorious benefactors" to Angelo. Angelo asks if they are not "malefactors" instead, and the constable replies that he does not know. Angelo asks Pompey what he is, and Elbow calls him a "parcel-bawd," or a partial bawd. It becomes clear that Elbow confuses words a lot, and so Angelo has difficulty questioning him. He does say that he found Pompey and Froth at a brothel. Froth confesses to working for Mistress Overdone, and Escalus tells him that prostitution is an illegal and punishable occupation, warning him not to be seen at the brothel again.
Escalus questions Elbow about other constables, telling him to bring the names of other worthy people. He then mourns the fate of Claudio, but says that there is no remedy for it.
This scene exists primarily for comic relief, distracting the audience momentarily from the issues at stake, particularly Claudio's imminent execution. Escalus is a noble character who acts as a straight-man to the dim-witted constable and the foolish clown. Elbow is a frivolous addition to the cast of characters, amusing because of his use of malapropisms, or misspoken phrases and words. He is sent to retrieve the criminals of Vienna, and he appears at various intervals performing this task and providing more pure comedy.
At the end of the scene, the tone shifts back to seriousness, as Escalus expresses his pity for Claudio. It is important that Escalus, as well as the provost, does not approve of the punishment to be administered to Claudio, and yet sees no way to convince Angelo to be more merciful. Angelo appears to be narrow-minded and stern; the other characters seem to fear him. There is a sense of apathy among the characters generally; it takes the Duke's intervention to promote movement, discussion, and action in them.