Letter 182: Whether in prosperity or adversity, in public life or in private — the standard of conduct does not change.

To Artemidorus. On the Psaltery. Concerning the superscription of the Psalms. When the composer of the melody [the Melopoios, the maker of the song] himself sang it, it was entitled "a psalm"; "A Song for David" (Psalm 80). But when he himself sang while another composed the melody, or when the melody for him was sung by others, or when it was referred to the Christ who came from him according to the flesh, then "A Psalm for David." For not all the writers of melodies sang, nor did all who sang write the melodies; rather, some did the one, others the other, and others accomplished both, since the divine Spirit assigned to each what was suited to him.

Τοῦ ψαλτηρίου. Περὶ τῆς τῶν Ψαλμῶν ἐπιγραφῆς. Ὅτε μὲν ὁ Μελοποιὸς ἐμελῴδει, ἐπεγράφετο ψαλμός· Ὠδὴ τῷ Δαυΐδ (80). Ὅτε δὲ αὐτὸς μὲν ἐμέλῳδει, ἄλλος δὲ ἐμελοποίει, ἢ εἰς αὐτὸν τὸ μέλος παρ’ ἄλλων ᾄδετο, ἢ εἰς τὸν ἐξ αὐτοῦ τὸ κατὰ σάρκα Χριστὸν ἀνήγετο, Ψαλμὸς τῷ Δαυΐδ. Οὐ γὰρ πάντες οἱ μελογράφοι ᾖδον, οὐδὲ πάντες οἱ ᾄδοντες ἐμελογράφουν· ἀλλ’ οἱ μὲν τοῦτο, οἱ δὲ ἐκεῖνο· οἱ δὲ ἀμφότερα διεπράττοντο, τοῦ θείου Πνεύματος ἑκάστῳ τὸ πρόσφορον ἀπονέμοντος.