TO MY VERY DEAR LORD AND MOST HONOURED BROTHER AMONG THE MEMBERS OF CHRIST, VALENTINUS, AND TO THE BRETHREN THAT ARE WITH YOU, AUGUSTIN SENDS GREETING IN THE LORD.
1. That Cresconius and Felix, and another Felix, the servants of God, who came to us from your brotherhood, have spent Easter with us is known to your Love. We have detained them somewhile longer in order that they might return to you better instructed against the new Pelagian heretics, into whose error every one falls who supposes that it is according to any human merits that the grace of God is given to us, which alone delivers a man through Jesus Christ our Lord. But he, too, is no less in error who thinks that, when the Lord shall come to judgment, a man is not judged according to his works who has been able to use throughout his life free choice of will. For only infants, who have not yet done any works of their own, either good or bad, will be condemned on account of original sin alone, when they have riot been delivered by the Saviour's grace in the layer of regeneration. As for all others who, in the use of their free will, have added to original sin, sins of their own commission, but who have not been delivered by God's grace from the power of darkness and removed into the kingdom of Christ, they will receive judgment according to the deserts not of their original sin only, but also of the acts of their own will. The good, indeed, shall receive their reward according to the merits of their own good-will, but then they received this very good-will through the grace of God; and thus is accomplished that sentence of Scripture, "Indignation and wrath, tribulation and anguish, upon every soul of man that does evil, of the Jew first, and also of the Gentile: but glory, honour, and peace to every man that works good; to the Jew first, and also to the Gentile."
Source: Letters (New Advent)