In this Catechism lesson from the late 1980's, Father teaches us about the different kinds of sin according to the method of Saint Thomas Aquinas.
Father covers the differences between Venial and Mortal sins, sins of the Flesh and sins of the Spirit, what constitutes a Mortal sin, the sins of the Angels and much more.
This catechism follows very closely Question 72 in the First Part of the Second Part of the Summa Theologica of Saint Thomas Aquinas.
Question 72 specifically asks the following questions:
- Whether sins differ in species according to their objects?
- Whether spiritual sins are fittingly distinguished from carnal sins?
- Whether sins differ specifically in reference to their causes?
- Whether sin is fittingly divided into sin against God, against oneself, and against one's neighbor?
- Whether the division of sins according to their debt of punishment diversifies their species?
- Whether sins of commission and omission differ specifically?
- Whether sins are fittingly divided into sins of thought, word, and deed?
- Whether excess and deficiency diversify the species of sins?
- Whether sins differ specifically in respect of different circumstances?
The question from the Summa Theologica being discussed here can be found online, here: http://www.newadvent.org/summa/2072.htm