Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 57

Chapter 57.—129.  Petilianus said:  "It is written, ‘Thou shalt not commit adultery.’  Each one of you, even though he be chaste in his body, yet in spirit is an adulterer, because he pollutes his holiness."

130.  Augustin answered:  These words also might be spoken with truth against certain both of our number and of yours; but if their deeds are condemned by us and you alike, they belong to neither us nor you.  But you wish that what you say against certain men, without proving it even in their especial case, should be taken just as if you had established it,—not in the case of some who have fallen away from the seed of Abraham, but in reference to all the nations of the earth who are blessed in the seed of Abraham.