Every judgement of conscience, be it right or wrong, be it about things evil in themselves or morally indifferent, is obligatory, in such wise that he who acts against his conscience always sins.

Thomas is held in the Roman Catholic Church to be the model teacher for those studying for the priesthood and indeed the highest expression of both natural reason and speculative theology. there must be a superlative which is the truest and noblest thing and so most fully existing. On the part of the Church however there is mercy which looks to the conversion of the wanderer wherefore Thomas Aquinas condemns not at once but "after the first and second admonition" as the Apostle directs: after that if he is yet stubborn the Church no longer hoping for his conversion looks to the salvation of others by excommunicating him and separating him from the Church and furthermore delivers him to the secular tribunal to be exterminated thereby from the world by death.

" He was the foremost classical proponent of natural theology and the father of Thomism. His influence on Western thought is considerable and much of modern philosophy was conceived in development or refutation of his ideas particularly in the areas of ethics natural law metaphysics and political theory. The study of his works according to papal and magisterial documents is a core of the required program of study for those seeking ordination as priests or deacons as well as for those in religious formation and for other students of the sacred disciplines (Catholic philosophy theology history liturgy and canon law).