On Nature and Grace (Latin: De natura et gratia) is an anti-Pelagian book by Augustine of Hippo written in AD 415.
It is a response to Pelagius's 414 book On Nature (Latin: De natura).
Before this work, Augustine did not seem to see Pelagius as a heretic, but On Nature and Grace seems to be a turning point in the Pelagian controversy.
[1] The work does not mention Pelagius by name, but by responding to De natura, Augustine for the first time engages Pelagius as an opponent.
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