Prudence
Especially in the first half of the novel, the vicar is defined by his sense of prudence. For him, prudence (or wisdom) involves living a life of moral righteousness, trusting in mankind's implicit goodness. However, the second half of the novel reveals the limits of such prudence. Through the vicar's many mishaps - several of which he could have prevented had he employed a more cynical view of people - Goldsmith suggests that man needs more than prudence to navigate the world's evils. Instead, man also needs fortitude and a willingness to doubt and question the motives of others. Certainly, the novel does not condone immoral behavior, but it does suggest that a delusional assumption of wisdom can often cause serious problems.
Fortitude
The theme of fortitude serves as the guiding force of the novel's second half. The Vicar of Wakefield has often been compared to the Bible's Book of Job, and with good reason. The characters, particularly the vicar, are subject to many trials and tribulations throughout the story, and must ultimately rely on intense fortitude in order to weather these trials. When faced with true calamity, the vicar must rid himself of pride, and recognize the limits of his prudence, so that he can become the true man of God he always thought himself to be. By the time he delivers his sermon on fortitude to George and the prisoners, he truly represents a man poised to weather difficulties through personal strength. The reader is thus exhorted to model his own behavior on the vicar's.
Religion
Religion is obviously an important theme in the novel, considering the protagonist's job. Though the book does have a moral message, it reflects an ambivalent relationship with God. Despite his flaws, the vicar does try to model a good, virtuous life for his family and strangers alike. And many of Goldsmith's contemporary critics were impressed by his ultimate message, that man must endure hardship on Earth in anticipation of a greater life in heaven. However, the vicar has a discernible lack of intimacy with God; he certainly tries to live a godly life, but does not necessarily engage in any deep prayer or communion. Instead, he uses his sanctimony to favor behavior he approves of, and to validate his more selfish desires for his family. The overall suggestion is that a sense of God permeates the vicar's life, but that it might often only operate on a superficial level.
Disguise and Deception
The novel is rife with disguise and deception. Characters are never who they seem to be, and adapt different masks, identities, and personas both to confuse the reader and each other. In many ways, this repeated trait reveals some of Goldsmith's view of humanity. The vicar and his family assume Squire Thornhill is a good person and that Mr. Burchell is not. Moses and the vicar are duped by Ephraim Jenkinson, and the vicar is fooled by Mr. Arnold's butler. The two rich, fashionable ladies prove to be frauds. All of this deception reinforces Goldsmith's point that prudence has limits, since the family eventually realizes that virtue alone cannot ensure success, happiness, or safety in a world of duplicity. The Primrose family lacks true wisdom because they assume their godly wisdom serves them well, and they as a result are almost destroyed.
Family
Family is extremely important to the vicar - he derives a great deal of pride and satisfaction in his wife and children. However, this love of family also serves to blind him to reality. He praises their excellent temperaments, and overlooks their flaws and foibles. Further, he lapses into a gentle hypocrisy because of his pride in them. Though he often outwardly argues that people should accept their station in life, the hopes of his daughters infect him, leaving him blind to the machinations of Squire Thornhill. The family thus operates as an insulated organism in the novel, and one that does not necessarily prove the most successful way of navigating the world. This is not to say that Goldsmith does not find value in the family; rather, he seems to counsel the reader that one must uphold one's individuality and discernment, and not fall prey to the cloistered ignorance that often comes from remaining too close to one's family.
Gender
Gender proves an interesting theme because of how closely the novel adheres to the traditional gender norms of 18th century British society. The men make the decisions and hold the power; the vicar is the unequivocal patriarch who determines the conduct of his family members. His daughters are vain and romance-oriented, and are notable only for their nubile, marriageable status. Arabella is viewed in the same way, despite being more genteel and elegant. Only the vicar and his sons are allowed to enter the public sphere and engage in commercial transactions. By contrast, when Olivia leaves the family home to elope with the squire, she is considered utterly ruined and beyond redemption. Her virtue is her most salient characteristic, as it was with all young women during the time. The novel is a perfect encapsulation of the way gender was viewed in Goldsmith's era, which is interesting considering how wonderfully he challenges narrative conventions throughout the story.
Social Class
In many ways, social class is one of the most pernicious forces in the novel. Despite the vicar's outward support of poverty, the Primrose family cannot accept having lost its upper-middle class status. Because they continue to see the world in terms of social class, they prove blind to Squire Thornhill's machinations, and question good people like Mr. Burchell and the Flamborough girls. Even as their attempts to act above their station embarrass them, the Primrose family continues to push for a certain level of appearance.
Goldsmith is clearly mocking their pretensions, and yet his views on class are a bit more nuanced than immediately apparent. While the squire is the grossest manifestation of the upper class, Sir William proves a benevolent and noble man. The sense is that money and title can corrupt, but also that they can be channeled in virtuous and altruistic ways. The Primrose family eventually does attain their desired social station after the vicar's fortune is restored and Sophia marries Sir William, but this success only comes after many trials that effectively curtail the family's pride and teach them the error of their pretensions.