In On Grace and Free Will, St. Augustine addresses a theological controversy that remains highly debated even in modern Christianity - the interplay between the sovereignty of God and human free will choice. During his own lifetime, particularly at the beginning of the fifth century, a British monk named Pelagius was considered to be the promoter of a view of human free will that emphasized man's ability to choose salvation of his own accord, without any Divine assistance. This idea was swiftly attacked and labeled as heretical by church leaders at the time.

In Augustine's eyes, the real danger of Pelagianism rested in its tendency to suggest that man, of his own free will, has the ability to earn his way to salvation. Such a view, taken to its logical ends, would result in a religion of works and merit. Instead, in On Grace and Free Will, Augustine points to the Scriptures to remind his readers that the grace of God is essential to the salvation of mankind. His reminder rings true for believers and seekers of all ages and his work remains widely read because of its complete and thorough treatment of one of the most foundational truths of Christianity.