There are several prevalent themes in Chekhov's "The Bet." There are questions about the value of wisdom and knowledge, life and existence, isolation, sacrifice and the corrupting power of money.
The value of wisdom and knowledge is apparent in the lawyer's character. Though he is not entirely unfazed by his self-imposed isolation, he persists because he finds value in educating himself. He is empowered by his pursuit of knowledge, and he gains wisdom through his reflections. While imprisoned, the lawyer ponders the nature of life and existence, studying theological and philosophical writings, leading to further reflection. His 15 years of isolation delivers him into a new reality, far removed from everyday life in society, yet he endures through the words of others.
There are three prominent examples of sacrifice in the story: the lawyer's sacrifice of his social life for 15 years to win a bet, the banker's sacrifice of his morality to kill and not lose the wager he can no longer pay and the lawyer's sacrifice of his winnings to be a man unaffected by material possessions. Ironically, while the lawyer frees himself of the corrupting power of money during his experience, the banker becomes so corrupted he convinces himself he should kill the lawyer to avoid paying.