One should think that with Lazaro's unseemly background, he would be the dishonest person, since he is a person from a broken family with a thief for a step-father and a mother who basically passes him off to be raised by a blind beggar. But actually, the real insight of the novel comes from his various encounters with the church. He is a rogue person with no real anchor, so his attachment to community is loose enough that he provides a unique insight into the nature of his religious community.
The rest of the characters in his community tend to accept the nature of the church as self-explanatory, so that if the church says that the church should be trusted, people automatically believe that. But Lazaro's difficult, frustrating life allows him to be more objective about the people who comprise the church. The book was considered so offensive to the church that it was forbidden to the public during the Spanish inquisition.
Meanwhile, his life goes on as a petty thief. Lazaro understands that life is a hustle, but over the course of the novel, he longs for something more stable than the street life, and he is sickened by his over-exposure to hypocrisy and dishonest clergymen. So, he decides to attain a life of stability in the ending of the story, which allows the novel to criticize "normal" life. He finds that death limits his stability in life, and when he finally settles on a girl for marriage, she cheats on him. Overall, the book is a cynical and satirical look at Spanish life.
