In the first part of the book he proves that the perseverance by which a man perseveres in Christ to the end is God’s gift; for that it is a mockery to ask of God that which is not believed to be given by God. Moreover, that in the Lord’s prayer scarcely anything is asked for but perseverance, according to the exposition of the martyr Cyprian, by which exposition the enemies to this grace were convicted before they were born. He teaches that the grace of perseverance is not given according to the merits of the receivers, but to some it is given by God’s mercy; to others it is not given, by His righteous judgment. Aeterna Press

In the first part of the book he proves that the perseverance by which a man perseveres in Christ to the end is God's gift; for that it is a mockery to ask of God that which is not believed to be given by God. Moreover, that in the Lord's prayer scarcely anything is asked for but perseverance, according to the exposition of the martyr Cyprian, by which exposition the enemies to this grace were convicted before they were born.

This treatise was written about 400 A.D. Concerning it Aug. in Retract. Book II. c. xviii., says: I have written seven books on Baptism against the Donatists, who strive to defend themselves by the authority of the most blessed bishop and martyr Cyprian; in which I show that nothing is so effectual for the refutation of the Donatists, and for shutting their mouths directly from upholding their schism against the Catholic Church, as the letters and act of Cyprian. Aeterna Press

I Wrote again to the same persons another treatise, which I entitled On Rebuke and Grace, because I had been told that someone there had said that no man ought to be rebuked for not doing God's commandments, but that prayer only should be made on his behalf, that he may do them. This book begins on this wise, "I have read your letters, dearly beloved brother Valentine."

Extract from Augustine's Retractions (Book II, Chapter 42): At that time also there came into my hands a certain book of Pelagius', in which he defends, with all the argumentative skill he could muster, the nature of man, in opposition to the grace of God whereby the unrighteous is justified and we become Christians. The treatise which contains my reply to him, and in which I defend grace, not indeed as in opposition to nature, but as that which liberates and controls nature, I have entitled On Nature and Grace. In this work sundry short passages, which were quoted by Pelagius as the words of the Roman bishop and martyr, Xystus, were vindicated by myself as if they really were the words of this Sixtus. For this I thought them at the time; but I afterwards discovered, that Sextus the heathen philosopher, and not Xystus the Christian bishop, was their author. This treatise of mine begins with the words: 'The book which you sent me.'"

I Wrote again to the same persons another treatise, which I entitled On Rebuke and Grace, because I had been told that some one there had said that no man ought to be rebuked for not doing God’s commandments, but that prayer only should be made on his behalf, that he may do them. This book begins on this wise, “I have read your letters, dearly beloved brother Valentine.”