The quote can be defined by many contexts, for example the truth can literally set you free and could help you avoid problems or that the truth could metaphorically set you free, by being truthful you remain true to yourself themselves. In the case of Matthew Poncelet, the truth had liberated him in a figurative sense; accepting the true nature of his crime would save his "soul" and lead him to be honest with himself. The quote also refers to the freedom of mind that admitting one's crimes would mean taking responsibility for one's actions that he had never committed before. This could be used in our daily life as a tool to stay sincere and honest