The Church often recognizes specific saints as "Doctors of the Church," who were exemplary teachers in various theological or spiritual topics. These holy men and women were given the official title of Doctor, which stems from the Latin root word docere, meaning “to teach.”
St. Augustine is one of those Doctors of the Church, but many have also called him more specifically the "Doctor of Grace."
Why is that? What does it mean?
Doctor of Grace
According to the Catholic Encyclopedia, "So amply and magnificently did Augustine develop his theory on the Church that, according to Specht "he deserves to be named the Doctor of the Church as well as the Doctor of Grace."
Fr. William Most explains in a note on St. Augustine on Grace and Predestination, "St. Augustine is called, rightly, the Doctor of Grace, for his great work against the Pelagians who practically denied the need of grace for salvation. Augustine showed very well our total dependence on God."
St. Augustine writes, "For not only has God given us our ability and helps it, but He even works [brings about] willing and acting in us; not that we do not will or that we do not act, but that without His help we neither will anything good nor do it."
He also writes, "If then your merits are God's gifts, God does not crown your merits as your merits, but as His gifts."
Basically, we are all in need of God's divine assistance, and St. Augustine was one of the foremost experts who helped develop the Church's views on the action of God's grace in our everyday lives.