1.

How much the arguments make for us, that is, for catholic peace, which the party of Donatus profess to bring forward against us from the authority of the blessed Cyprian, and how much they prove against those who bring them forward, it is my intention, with the help of God, to show in the ensuing book. If, therefore, in the course of my argument, I am obliged to repeat what I have already said in other treatises (although I will do so as little as I can,) yet this ought not to be objected to by those who have already read them and agree with them; since it is not only right that those things which are necessary for instruction should be frequently instilled into men of dull intelligence, but even in the case of those who are endowed with larger understanding, it contributes very much both to make their learning easier and their powers of teaching readier, where the same points are handled and discussed in many various ways. For I know how much it discourages a reader, when he comes upon any knotty question in the book which he has in hand, to find himself presently referred for its solution to another which he happens not to have. Wherefore, if I am compelled, by the urgency of the present questions, to repeat what I have already said in other books, I would seek forgiveness from those who know those books already, that those who are ignorant may have their difficulties removed; for it is better to give to one who has already, than to abstain from satisfying any one who is in want.