A grave blockhead should always go about with a lively one -- they show one another off to the best advantage.

Summary

This quote suggests that it is beneficial for someone who lacks intelligence or wit to be in the company of someone who possesses these qualities. The "grave blockhead" refers to a dull or unintelligent person, while the "lively one" represents a sharp or clever individual. By being in each other's company, they can complement each other, making the dull person appear smarter in contrast to the witty one. It implies that surrounding oneself with intellectually superior individuals can enhance one's own reputation or image.