“The fathers did not themselves believe that they, or their companions, were always right. Augustine found himself mistaken in some cases and did not hesitate to retract his errors.”

Prologue as translated in Readings in European History, Vol. I (1904) edited by James Harvey Robinson, p. 450
Sic et Non (1120)
Context: Doubtless the fathers might err; even Peter, the prince of the apostles, fell into error: what wonder that the saints do not always show themselves inspired? The fathers did not themselves believe that they, or their companions, were always right. Augustine found himself mistaken in some cases and did not hesitate to retract his errors. He warns his admirers not to look upon his letters as they would upon the Scriptures, but to accept only those things which, upon examination, they find to be true.
All writings belonging to this class are to be read with full freedom to criticize, and with no obligation to accept unquestioningly; otherwise they way would be blocked to all discussion, and posterity be deprived of the excellent intellectual exercise of debating difficult questions of language and presentation.