This is the first of five volumes of Augustine's sermons on the psalms. Mostly they are actual sermons, preached before an audience, and here you can see Augustine's speaking skills at their finest.
He took the psalms seriously, as we all should do, and these texts consider each line of each psalm, illuminating them by other scriptural references, by his personal experiences, and the fruits of his prayer life. Augustine organized his life in such a way that he spent most of his time praying, thinking about the faith, and talking about it with the other members of his diocese; and the fruits of this labor are apparent in this collection. Every word comes from the heart; this was not a mere intellectual exercise.
On materialism: "By enemies of this providential dispensation which was brought about by Jesus Christ, and him crucified, we ought in a general sense to understand all who forbid us to believe in things beyond our experience, while themselves promising certain knowledge. This is what all heretics do, and the same holds for those who among superstitious Gentiles pass for philosophers."
On scandals in the church: "God's people that is now sorely afflicted, and suffers tribulation from being so fiercely tempted, from such great scandals, persecutions and oppression. People who are making no progress in the Church are unaware of these spiritual torments; they think there is peace. But only let them begin to advance and they will experience the oppression under which it labors, because it was when the crop had grown and begun to yield its grain that the tares also appeared (Mt 13:26). Fuller knowledge means increased sorrow."
So you can see that nothing really has changed in the 1,600 years since Augustine wrote. The issues he wrestled with are still the same issues we deal with today; human nature hasn't changed since God breathed life into Adam. Only technology and the circumstances of life change; people never actually change. For this reason, any argument for change that starts with "Due to the new nature of modern man" or "due to modern man's new understanding" is an argument that must be false.