Don't forget either, you unhappy man, that voluntary is much heavier than enforced imprisonment. The idea that you have the right to free yourself at any moment will poison the whole of your life in the cell.
The banker makes this comment to the lawyer during the party before they agree on the terms of the bet. Although the banker makes many poor judgements, his comment here hints at the dual way captivity works in the story. A person’s mental state can be as much of a prison as their physical state. Although this prediction does not appear to bear out for the lawyer, the banker, too, has placed himself in a prison of his own making by accruing debts. The banker’s belief that he can free himself by killing the lawyer poisons his soul, nearly turning him into a murderer.
On my own clear conscience and before God who sees me I declare to you that I despise freedom, life, health, and all that your books call the blessings of the world.
The lawyer writes these words in the letter he crafts to announce his abdication of the bet. The lawyer here has rejected the very notion of freedom, as it is traditionally meant, because he believes he has found real freedom and truth through his study while in captivity. The lawyer’s epiphany illustrates the idea that freedom is more than a physical state—it’s also a state of mind. Whether we believe the lawyer to have reached an enlightened freedom or that he stays trapped in a deeper prison of his mind, the point remains that captivity is more than just a lack of physical liberty.