Since you do not wish to understand the “many” he said later as meaning the “all” he said first, you declare he said “many” to keep us from thinking he meant “all”. You could do likewise about the seed of Abraham to whom all nations were promised, and say not all nations were promised him, because we read in another passage: “I have made thee a father of many nations.” Sound thinking shows that Scripture speaks in this way because there can be an “all” which are not “many,” as we speak of all the Gospels, yet they are only four in number. There can also be “many” which are not “all,” as we say many believe in Christ, yet not all believe; the Apostle says: “All men have not faith.” In the words, “In your seed all nations will be blessed” and “I have made thee a father of many nations,” it is clear that the same nations that are all are also many, and the same that are many are all. Similarly, when it is said that through one, sin passed unto all, and later, that through the disobedience of one, many were constituted sinners, those who are many are also all. In like manner, when it is said: “By the justice of the one the result is unto justification of life to all men,” and again: “By the obedience of the one many will be constituted just,” none is excepted; we must understand that those who are many are all not because all men are justified in Christ, but because all who are justified can be justified in no other way than in Christ. We can also say that all enter a certain house through one door, not because all men enter that house, but because no one enters except through that door. All, then, are unto death through Adam; all unto life through Christ. “As in Adam all die, so in Christ all will be made to live.” That is to say, from the first origin of the human race, none is unto death except through Adam, and through Adam none is unto anything but death; and none is unto life except through Christ, and through Christ none is unto anything but life.- Augustine, Against Julian, Book VI, Chapter 24, Section 80 (see Ancient Voices for more)
I think this quotation is interesting for a number of reasons:
1) We see Augustine making a similar (though not precisely the same) distinction between "all in Adam" and "all in Christ" that typical Calvinist exegesis concludes;
2) We see that Augustine held to exactly four gospels;
3) We see that Augustine concluded that all who died received this curse via Adam (which would, in Augustine's theology, include Mary the mother of our Lord).