The Duke arrives outside the town, in his own clothes, with Friar Peter. He tells the friar to deliver some letters, and also to bring Flavius to him. Varrius enters, and they walk together.
Isabella and Mariana are standing by the city gate. Isabella is nervous about accusing Angelo, but Mariana tells her to obey the Duke and the Friar. Friar Peter approaches and tells them that he will find a place for them near the Duke.Read a translation of Act IV, Scenes iii-vi →
Things become more muddled just as they are on the verge of clarification. The Duke's plans are carried out, and he instigates a new scheme to save Claudio and Barnadine both. Barnadine refuses to be executed, perhaps even sensing that the Duke and the provost see his life as worthless. His assertion that he will not die is a statement of the sanctity of life in general. The convenient death of the pirate matches the convenient existence of Mariana in its incredibility, and the Duke's attitude encourages us simply to follow along as all the other characters do. Angelo emerges as quite an oblivious figure, as he is tricked by Mariana's substitution for Isabella and a pirate's substitution for Claudio all in the space of one night and morning. Here Shakespeare truly demands that we suspend our disbelief.
The Duke's lie to Isabella is undoubtedly unkind, causing her great distress and anger. There are some possible motivations for this; perhaps, for instance, he believed that she would not argue passionately against Angelo once the point became irrelevant. However, it is likely that he wants to surprise her dramatically before asking for her hand in marriage.
The Duke does not immediately reveal his dual identity, still enjoying the intrigue which only he fully comprehends. To some extent, he is playing with his subjects, making them believe that they act of their own volition while manipulating them. He is also testing them, perhaps to determine how worthy they are of their positions. Isabella no doubt falls into this examination of virtue, and she passes by refusing Angelo's proposals and obeying the Duke and Friar wholeheartedly.