Themes
Revenge and mercy
Moranzone designs a revenge that is slow and intimate: Guido must eat the Duke's bread, win his trust, then wake him before he kills him. The play then questions that code. By Act III Guido has decided that 'Vengeance is God's' and plans to leave the dagger on the sleeping Duke's breast, a mercy he calls the noblest vengeance he can take. Moranzone names himself Revenge, and Beatrice, turned vengeful after Guido rejects her, says the word is branded in scarlet letters on her forehead. Her revenge, pointing Guido out to the soldiers, leads to both their deaths.
Love as a sacrament
Guido tells Moranzone that 'Love is the sacrament of life', that it cleanses men and that 'The wicked cannot love'. Beatrice takes the same faith to its extreme: she kills her husband because love has made him the barrier, and says the love of man 'Turns women into martyrs'. Guido at first answers that she has murdered love itself. The last act reverses his judgement. He declares that they do not sin at all who sin for love, and Beatrice dies saying 'I have loved much', words that ask for the forgiveness her peaceful face seems to receive.
Buying and selling
The language of the market runs through the play. Lorenzo was 'sold', 'Bartered and bargained for in privy market' by his friend. The Duke says every man among his lords has his price, pays a citizen two ducats to cheer him, and says he bought his Duchess with three towns he never handed over. Beatrice says women are 'bought rather, sold and bartered, Our very bodies being merchandise'. Moranzone fears that the wife who betrays Guido 'Would sell the son in turn', and the dying Beatrice offers Padua for one more hour of life.
Power, law and justice
The Duke rules by contempt, telling the starving that poverty is a Christian virtue and warning his wife that she has no friend in Padua. His death puts power in Beatrice's hands, and in Act IV she uses it as he would have done, declaring 'We are not bound by law, But with it we bind others' and tearing a page out of the statute book. The Lord Justice will not be moved. The law that forbids Guido to speak as a traitor lets him speak as a foreigner, and the same law condemns him once he confesses.
The lot of women
Left alone after the Duke's threats in Act II, Beatrice says that women are their husbands' 'chattels' and 'common slaves', less dear than a hound. She came to Padua as a bargain between the Duke and her father, and the Duke's second Duchess lies in the chapel for asking him by what right he ruled her. In Act III she tells Guido 'How differently do we love from men!' and describes a workman's wife who is beaten and still loves. The play gives her the greatest passion and the greatest guilt, and lets her die forgiven.
Guilt and forgiveness
After the murder Beatrice cannot sleep for fear of dreams, and in the dungeon she refuses Guido's kiss because her lips are 'soiled'. She tells him 'We are each our own devil, and we make This world our hell', rejecting his excuse that some devil tempted her. Guido answers by sharing the guilt: his soul was murderous though his hand refused, while her hand killed though her soul was pure. The final stage direction settles the question in her favour, describing her dead face as the marble image of peace and the sign of God's forgiveness.