24 In his Controversies, although the holy Doctor made large use of the polemical literature of the past, he exhibits nevertheless a controversial method quite peculiarly his own. In the first place, he proves that no authority can be said to exist in the Church of Christ unless it had been bestowed on her by an authoritative mandate, which mandate the ministers of heretical beliefs in no way can be said to possess. After having pointed out the errors of these latter concerning the nature of the Church, he outlines the notes of the true Church and proves that they are not to be found in the reformed churches, but in the Catholic Church alone. He also explains in a sound manner the Rule of Faith and demonstrates that it is broken by heretics, while on the other hand it is kept in its entirety by Catholics. In conclusion, he discusses several special topics, but only those leaflets which treat of the Sacraments and of Purgatory are not extant. In truth, the many explanations of doctrine and the arguments which he has marshaled in orderly array, are worthy of all praise. With these arguments, to which must be added a subtle and polished irony that characterizes his controversial manner, he easily met his adversaries and defeated all their lies and fallacies.
Source: Rerum Omnium Perturbationem (Vatican.va)