This section of the Summa Theologiae investigates the nature of injustice as a specific vice opposed to the virtue of justice. Thomas Aquinas, a 13th-century Dominican friar and scholastic philosopher, utilizes Aristotelian logic and Christian scripture to define the moral parameters of human action. He argues that injustice consists in the violation of the rights of others, whether through the deprivation of property or the failure to render what is due, establishing a framework for understanding moral culpability.

Scholars and theologians view this text as a foundational component of Western moral philosophy and natural law theory. Readers frequently note the high density of the scholastic prose, which requires careful attention to the specific dialectical structure of the questions and objections.