And in the same way the doings there narrated are to us material for wonder and examples to be followed, but not in any sense things we have done ourselves.
With this book [the Psalms], however, though one does read the prophecies about the Saviour in that way, with reverence and with awe, in the case of all the other Psalms it is as though it were one’s own words that one read.
And anyone who hears them is moved at heart, as though they voiced for him his deepest thoughts.
[…] No one would ever speak the patriarchs’ words as though they were his own, or dare to imitate the utterance of Moses or use the words of Abraham concerning the great Isaac, or about Ishmael and the home-born slave, as though they were his own, even though like necessity oppressed him.
Neither, if any man suffer with those that suffer or be gripped with desire of some better thing, would he ever say as Moses said, Show me Thyself (Ex 33:13), or If Thou remittest their sin; then remit it; but if not, then blot me out of Thy book that Thou hast written (Ex 32:32).
No more would any one use the prophets’ words of praise or blame as though they were his own, or say, The Lord lives, in Whose sight I stand today. For he who reads those books is clearly reading not his own words but those of holy men and other people about whom they write.
But the marvel with the Psalter is that, barring those prophecies about the Saviour and some about the Gentiles, the reader takes all its words upon his lips as though they were his own.
Each one sings the Psalms as though they had been written for his special benefit, and takes them and recites them, not as though someone else were speaking or another person’s feelings being described, but as himself speaking of himself, offering the words to God as his own heart’s utterance, just as though he himself had made them up.
Not as the words of the patriarchs or of Moses and the other prophets will he reverence these: no, he is bold to take them as his own and written for his very self.
Whether he has kept the Law or whether he has broken it, it is his own doings that the Psalms describe; every one is bound to find his very self in them and, be he faithful soul or be he sinner, each reads in them descriptions of himself.
Athanasius of Alexandria (c.293-373): Letter to Marcellinus in Athanasius: The Life Of Antony And The Letter To Marcellinus, translated by Robert C. Gregg; Paulist Press, New York; pp. 101-129; 1980 @ Athanasius.com (slightly adapted).