Summary based on https://www.newadvent.org/summa/3100.htm

The text provides a detailed scholastic examination of simony, defining it as the willful act of buying or selling spiritual things or things connected to them, often referred to as a heresy. It uses a question-and-answer format to address numerous objections regarding the definition, specifically debating whether the sin lies in the intentional will to commit the act and detailing why spiritual matters cannot be subject to earthly contracts. The discussion also delineates lawful and unlawful payments related to clerical support and services, clarifying that providing for a minister's livelihood is distinct from paying for spiritual grace, and explores appropriate punishments for simoniacs, including the forfeiture of what was improperly acquired. Ultimately, the source serves as a theological and legal treatise condemning the corruption of spiritual transactions.