St. Alphonsus Liguori’s Moral Theology has long been praised and held in the highest regard by the Church, covering every moral question of his day. This first ever English translation features book 4 of the Theologia Moralis, on The First through Sixth Commandments. These will cover topics as broad as the sin of divination, worshiping demons, blasphemy, oaths, vows, and when they are binding; when you must go to Mass and abstain from work, as well as considerations on the fourth commandment in regard to obedience, the fifth in terms of murder, just war and abortion, and in the 6th, adultery and the various sins against chastity.

The famous theologian Reginald Garrigou Lagrange, O.P. declared:

[The Casuistic method] was inefficacious in urging men to lead good lives, [and] tends to laxism. … But during this period there appeared a man, sent by God, to remedy the evils of casuistry. This man was St. Alphonsus Liguori, doctor of the Church, founder of the Redemptorists, renowned author of many works, ascetic and moral, highly praised by various popes. He is rather practical than speculative. As founder of aequiprobabilism, he cleansed casuistry from the defects of probabilism and laxism.

Reginald Garrigou-Lagrange Beatitude, c. II, p. 13.

One of St. Alphonsus’ names is Doctor Moralis, the moral doctor. This name is deserved for three reasons: 1) his work Theologia Moralis, translated into English here for the first time, as well as various other works, treated moral theology with a thoroughness like no other work of a prior saint. 2) St. Alphonsus was a true scholar by mastering virtually all contributors in the field of moral theology up to his own time. Like St. Thomas who was known for his synthesis of theology in general, St. Alphonsus is clearly a master of synthesizing the various moral authors throughout time. … 3) He addressed moral problems that had not been addressed by St. Thomas himself or other authors. … St. Alphonsus provides a thoroughness to moral theology which is very much needed today, in which approaches are often not based upon reality, the natural law, or sound reasoning.

Fr. Chad Ripperger, PhD

Volume 2 is taken from Book 4 of the Moral Theology.