Nicene and Post-Nicene Fathers, Vol. II:
On Christian Doctrine: Chapter 31

Chapter 31.—Apology for the Length of the Work.

64.  This book has extended to a greater length than I expected or desired.  But the reader or hearer who finds pleasure in it will not think it long.  He who thinks it long, but is anxious to know its contents, may read it in part.  He who does not care to be acquainted with it need not complain of its length.  I, however, give thanks to God that with what little ability I possess I have in these four books striven to depict, not the sort of man I am myself (for my defects are very many), but the sort of man he ought to be who desires to labor in sound, that is, in Christian doctrine, not for his own instruction only, but for that of others also.