As a character, Sam Weller complements Mr. Pickwick, just as Sancho Panza complements Don Quixote. Whereas Mr. Pickwick is innocent and elderly, Sam is experienced and young, the most intelligent character in the novel. If Mr. Pickwick loses his temper easily, Sam is quite self-possessed. While Mr. Pickwick has no romantic intentions, Sam carries on a courtship through much of the novel. One really cannot discuss Sam Weller without reference to Mr. Pickwick.
This is partly functional, since Sam's life is thoroughly intertwined with his master's, as a servant, ally, and son-figure. But it is also spiritual. Dickens implies that Sam's practical knowledge should be in the service of Mr. Pickwick's Christian principles. Mr. Pickwick gives Sam purpose, and Sam gives Mr. Pickwick the practical basis to effect the purpose. However, each is a unique and delightful personality in his own right.