Patrick discusses a caller's question about how intentionally eating meat on Fridays used to be considered a mortal sin by the Catholic Church. He explains that this was a discipline, not a doctrine, which the Church changed from a mortal sin to a venial sin or no sin after Vatican II while still encouraging penitential practice on Fridays. Patrick cites Acts 15 to show that the early Church had the authority to adjust disciplinary practices that were considered sinful to violate at the time, demonstrating that the Church can change the gravity of certain sins regarding matters of discipline.