The Enchiridion by St. Augustine
Chapter 24.--The Secondary Causes of Evil are Ignorance and Lust.
This is the first evil that befell the intelligent creation -- that is, its first privation of good. Following upon this crept in, and now even in opposition to man's will, ignorance of duty, and lust after what is hurtful: and these brought in their train error and suffering, which, when they are felt to be imminent, produce that shrinking of the mind which is called fear. Further, when the mind attains the objects of its desire, however hurtful or empty they may be, error prevents it from perceiving their true nature, or its perceptions are overborne by a diseased appetite, and so it is puffed up with a foolish joy. From these fountains of evil, which spring out of defect rather than superfluity, flows every form of misery that besets a rational nature.