. . . no one will love what he has no prospect of making his own by understanding; faith without the hope of understanding would be no more than compliance to authority (Brown, Augustine of Hippo. 279).
No separation of faith and reason. No opposition. Certainly no warning, ever, against the dangers of theology.
The thoroughly modern, and I should say, thoroughly erroneous antithesis between love and logic, feeling and reason, heart and head, practical and doctrinal, etc. had not meaning for him. Augustine writes no separate treatise concerning the theology of piety or devotion, simply because all of his works, from Contra Academicas to The City of God must be understood as such. And I might add, they all should be read devotionally.
Augustine’s devotion is theologically stimulated and regulated just as his theologizing is devotionally sustained and controlled. Thus the authenticity of a man’s piety is properly tested by the clarity and profundity of his theology and conversely the genuineness of his theology is properly tested by the intensity of his devotion.