Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 68

Chapter 68.—151.  Petilianus said:  "‘Blessed are the pure in heart:  for they shall see God.’  When will you see God, who are possessed with blindness in the impure malice of your hearts?"

152.  Augustin answered:  Wherefore say you this?  Can it be that we reproach all nations with the dark and hidden things which are declared by men, and do not choose to understand the manifest sayings which God spake in olden time of all the nations of the earth?  This is indeed great blindness of heart; and if you do not recognize it in yourselves, that is even greater blindness.