Prologue

Those who sail upon the sea are in the habit of feeling grateful and of conveying their thanks to those by whose help hazards have been avoided. Fires are lit, cries are sent out, and signals are erected by which the swirling Scylla, the whirling Charybdis, concealed rocks, and the pulling and gripping of Syrtes can be safely avoided by sailors. So also thanks are most properly owed to those who by their service warn of threats which endanger human salvation; and he who does not repay his debts is deservedly to suffer the loss of his salvation for his ingratitude towards kindness. Moreover, there is no one who does not know that salvation is impeded by the vices and it is important that out of love the vices of our neighbours are publicly singled out for avoidance. Indeed human life is more turbulent than any sea you please, and its dangers cannot be evaded unless their signs are made known. To this work, however, I am driven by the stimulus of the public utility and your commands, although I am aware of nothing within me that might rouse the attention of readers, being in any case a defenceless and weak man whose life is adequate as an example neither of moral sense nor of learned knowledge nor of good works. For this reason it is complained against me by many that I should keep still; it is said that nothing, even the praise of virtue, is splendid in the mouths of sinners.