David, the king of Israel, is an outstanding figure in Biblical history. Exceptionally talented, he left many wonderful works in various fields: religion, politics, and art. However, he was not free of errors, or even of committing crimes, yet he was capable of rising up from them through penitence and invoking the God of mercy. This is most evident after he had committed adultery with Bathsheba and led her husband Uriah the Hittite to death, as well as after the census. I discuss these cases and also deal with the penitential psalms, which reflect David’s attitude. In the second part, I analyze Mozart’s cantata Davide penitente (KV 469), in which he used the music from the Great Mass in C Minor, K. 427 c-moll to the Italian Psalm Paraphrases of the eighteenth century. I discuss the origins of the piece and of the libretto and comment on it at the musical and verbal level. The cantata is a harmonious synthesis in which the rich music complements the inspired words, reflecting its internal tension and emotions. Listening to this composition, we can more fully experience the contents contained within the Biblical text and delve into David’s dramatic world, which is always illuminated by God’s grace.