What is the lawyer trying to tell the banker in his note when he states "To show that I despise all that you live by, I give up the two million [dollars] I once so desired."
Can your money buy wisdom?
The lawyer spends fifteen years in enforced solitude. During that time he is forced to meditate, to commune with himself. He is an intelligent man and is not unlike many of the Eastern mystics who spend years in solitary meditation and give up all their material possessions because they have come to believe that enlightenment and peace of mind are only obtainable through forgetting the desire for worldly things. It is not the things but the desire for things that causes unhappiness. The prime example is Siddhartha, who gave up his royal status and even exchanged clothes with a beggar. He lived on one bowl of food a day, mostly rice, and he obtained the food by begging. He had no home but was said to live under a tree or in other similar humble accommodations. He became the Buddha and started a religion which has now spread all over the world. Herman Hesse's novel Siddhartha (ttp://www.enotes.com/topics/siddhartha) has long been a cult favorite of young readers. Mahatma Ghandi is another man who scorned material possessions. But they had many predecessors who are recorded in the Bhagavad Gita and in older Hindu scripture.
The lawyer is a modern man, but solitude leads him down a similar path. According to the eNotes Summary:
The lawyer was imprisoned in the banker’s garden house in complete solitude, permitted no visitors, no letters, no newspapers. He could write letters, however, and he was permitted books, music, wine, and tobacco. The banker observed the progress of the young lawyer’s adaptation to his imprisonment. During the first year, he read light books and played the piano. In the second year, he ceased being interested in music but turned to great literature. In the fifth year, he loafed, drank wine, and played the piano. Then for four years he studied languages, history, and philosophy before moving to the New Testament and to theology. Finally, his reading became eclectic.
The prisoner studies languages for four years because he wants access to works that were not available in the languages he already knew, which were Russian and probably Latin and French. Obviously he finally settled on religious and philosophical answers to his questions and became content. When he scorns to take the banker's two million rubles, he is demonstrating to the banker, as well as to himself, that he has reached a state of supreme enlightenment in which he values the understanding of truth exclusively and has no use for money. By losing the bet he has won. The banker's obsession with having money and making more money has only caused him unhappiness and anxiety. He has been driven to the point where he is ready to commit murder to keep from having to pay the prisoner the two million rubles he promised. This is not a typical Chekhov story. The bet the two men make seems weird and even improbable, but the outcome seems perfectly credible. A lot can happen to a man who spends fifteen years in solitude.