A moral failure is a person who abuses the trust of other people for their own gain. Moral failures are hypocrites, people who pretend to be one thing and are really another. Both Frate Timoteo and Sostrata use their positions of trust for worldly purposes.

Frate Timoteo is a moral failure because he freely uses his status as friar for his personal monetary gain. Innocent people trust him because he is a clergyman, and therefore, they think he is a true man of God and morally pure. However, he will twist the word of God to persuade people to do immoral things—as long as he is well paid for the work.

In this play, he persuades the innocent Lucrezia to sleep with a man who is not her husband in return for money. As he says as he enters into the plot:

Messer Nicia and Callimaco are rich, and I can get plenty out of them both in different ways. And I need not fear anything, for … it’s as little to their advantage as to mine to spread the word. ... I do fear, however, that as Madonna Lucrezia is upright and good there will be difficulties. Nevertheless it is through her goodness that I will get at her.

Sostrata, Lucrezia's mother, is a moral failure because she is willing to enter into Callimaco's plot and betray her daughter and son-in-law by convincing them it is not a sin to allow Lucrezia to have sex with another man. As Sostrata says to Nicia:

People always say that a wise man must choose the lesser of two evils. If this is the only solution for having children, you must take it.