"Nature has not got two voices, you know, one of them condemning all day what the other commands"

The quote by Marquis de Sade explains the concept that nature does not have inconsistent voices, with one condemning what the other demands. This can be translated as a commentary on the human tendency to overlook or go against what nature dictates for personal gain or beliefs. The Marquis is indicating that nature has one voice, which voice is law. By not sticking to it, human beings are producing an incongruity that is eventually damaging to the natural order of things. The quote can be viewed as a call to regard and honor the balance of nature, instead of simply using it for our own functions without thinking about the consequences.