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

p. 425

Book II.

In which Augustin proves that it is to no purpose that the Donatists bring forward the authority of Cyprian, bishop and martyr, since it is really more opposed to them than to the Catholics.  For that he held that the view of his predecessor Agrippinus, on the subject of baptizing heretics in the Catholic Church when they join its communion, should only be received on condition that peace should be maintained with those who entertained the opposite view, and that the unity of the Church should never be broken by any kind of schism.