The Enchiridion of Augustine, by Saint Augustine. Part I.

The Enchiridion, Manual, or Handbook of Augustine of Hippo is alternatively titled, "Faith, Hope, and Love". The Enchiridion is a compact treatise on Christian piety, written in response to a request by an otherwise unknown person, named Laurentis, shortly after the death of Saint Jerome in 420. It is intended as a model for Christian instruction or catechesis. 

As the title indicates, the work is organized according to the three graces necessary for the Christian worship of God: Faith, Hope and Love. Under Faith, Augustine explains the use of the Apostles' Creed, in teaching Christian doctrine and in refuting heresies. Under Hope, he briefly explains the Lord's Prayer as a model of Christian prayer. The final part is a discourse on Christian love. (From Wikipedia.)