A systematic dogmatic treatment defines and distinguishes actual and habitual (sanctifying) grace, explaining actual grace as transient supernatural assistance and habitual grace as an enduring sanctifying habit. It analyzes the nature, division, and properties of actual grace — necessity, gratuity, universality — and addresses divine predestination and reprobation. The relation between grace and free will is examined through debates involving Protestant and Jansenist critiques and theological responses such as Thomism, Augustinianism, Molinism, and congruism. The account of justification traces the genesis and effects of sanctifying grace, discusses faith and preparatory acts, characterizes the state of justification, and considers the merit and requisites of good works.