Monseigneur Bienvenu, whose full name is Monseigneur Charles-Francois-Bienvenu Myriel, also called the Bishop of Digne, is the most important character introduced in Chapter 12 of Book 1. He is also one of the most vital characters in the book due to the changes he creates. Monseigneur is described as "poor, humble, [and] retiring." In fact, Hugo spends a great deal of time in Chapter 12 characterizing Monseigneur Bienvenu's humble character. Hugo does so by describing a paradox. He describes all of the ambition found within the Catholic Church. He describes priests pushing to become bishops, then pushing to become archbishops, then cardinals, then climbing all the way up to becoming the Grace of Eminence and then finally the Holiness. Hugo also argues in this chapter that it is this sort of ambition that society recognizes as success; society especially recognizes ambition as monetary success, as we see in Hugo's lines:
Win in the lottery, and behold! you are a clever man. He who triumphs is venerated. Be born with a silver spoon in your mouth! everything lies in that. Be lucky, and you will have all the rest; be happy, and people will think you great. (Ch. 12)
But Hugo characterizes Bienvenu as contradicting society's typical nature. Instead, he is "poor, humble," and ready to retire. He is not, however, described as a powerless or unsuccessful man. On the contrary, the priests who have been ordained under him have become very successful, even obtaining positions with the "archbishops of Aix or of Auch" (Ch. 12). Therefore, Hugo is presenting Bienvenu's character as paradoxical with respect to what is accepted by society. Though he is successful and powerful, he is "poor, humble," and ready to be done with his career.
Characterizing Bienvenu as humble prepares the reader for what is soon to come. We see that Bienvenu is truly a man of his faith. So much so that later we understand why he alone was willing to reach out to Jean Valjean, taking him in under his wing when no one else would. Not only that, he gives Valjean the saving grace and redemption he needs to become a new man; Bienvenu redeems Valjean by giving him the silver, including both candlesticks, Valjean had stolen, telling him to use the money to become "an honest man," resulting in the changed Valjean we see throughout the rest of the book (Book 2, Ch. 12).