Iamblichus, De Vita Pythagorica

ἔτι τοίνυν σύμπαν τὸ Πυθαγορικὸν διδασκαλεῖον τὴν λεγομένην ἐξάρτυσιν καὶ συναρμογὰν καὶ ἐπαφὰν ἐποιεῖτο μέλεσί τισιν ἐπιτηδείοις εἰς τὰ ἐναντία πάθη περιάγον χρησίμως τὰς τῆς ψυχῆς διαθέσεις. ἐπί τε γὰρ εὐνὰς τρεπόμενοι τῶν μεθ’ ἡμέραν ταραχῶν καὶ περιηχημάτων ἐξεκάθαιρον τὰς διανοίας ᾠδαῖς τισι καὶ μελῶν ἰδιώμασι καὶ ἡσύχους παρεσκεύαζον ἑαυτοῖς ἐκ τούτου καὶ ὀλιγονείρους τε καὶ εὐονείρους τοὺς ὕπνους, ἐξανιστάμενοί τε ἐκ τῆς κοίτης νωχελίας πάλιν καὶ κάρους δι’ ἰδιοτρόπων ἀπήλλασσον ᾀσμάτων. ἔστι δὲ καὶ ὅτε ἄνευ λέξεως μελισμάτων ὅπου τε καὶ πάθη καὶ νοσήματά τινα ἀφυγίαζον, ὡς φασίν, ἐπᾴδοντες ὡς ἀληθῶς, καὶ εἰκὸς ἐντεῦθέν ποθεν τοὔνομα τοῦτο εἰς μέσον παρεληλυθέναι τὸ τῆς ἐπῳδῆς. οὕτω μὲν οὖν πολυωφελεστάτην κατεστήσατο Πυθαγόρας τὴν διὰ τῆς μουσικῆς τῶν ἀνθρωπίνων ἠθῶν τε καὶ βίων ἐπανόρθωσιν.

Moreover, the whole Pythagorean school practised what was called 'preparation', 'attunement' and 'contact', usefully turning the dispositions of the soul towards the opposite passions by means of certain suitable melodies. For when they were going to bed, they cleansed their minds of the day's disturbances and echoing noises by certain songs and distinctive melodies, and by this prepared for themselves quiet sleep, with few and good dreams; and on rising from bed they again rid themselves of sluggishness and heaviness by songs of a special kind. And there were times when [they used] melodies without words; and they healed certain passions and diseases, as they say, by truly singing charms over them; and it is likely that it was from here somehow that this word 'charm' (epōidē) came into common use. In this way, then, Pythagoras established the correction of human characters and lives through music as something of the greatest benefit.

ἐκ δὴ τούτων φανερὸν γέγονεν ὅτι τὴν ἀριθμῷ ὡρισμένην οὐσίαν τῶν θεῶν παρὰ τῶν Ὀρφικῶν παρέλαβεν. ἐποιεῖτο δὲ διὰ τῶν αὐτῶν ἀριθμῶν καὶ θαυμαστὴν πρόγνωσιν καὶ θεραπείαν τῶν θεῶν κατὰ τοὺς ἀριθμοὺς ὅτι μάλιστα συγγενεστάτην. γνοίη δ’ ἄν τις τοῦτο ἐντεῦθεν· δεῖ γὰρ καὶ ἔργον τι παρασχέσθαι εἰς πίστιν τοῦ λεγομένου. ἐπειδὴ Ἄβαρις περὶ τὰ συνήθη ἑαυτῷ ἱερουργήματα διετέλει ὢν καὶ τὴν σπουδαζομένην παντὶ βαρβάρων γένει πρόγνωσιν διὰ θυμάτων ἐπορίζετο, μάλιστα τῶν ὀρνιθείων· τὰ γὰρ τῶν τοιούτων σπλάγχνα ἀκριβῆ πρὸς διάσκεψιν ἡγοῦνται· βουλόμενος ὁ Πυθαγόρας μὴ ἀφαιρεῖν μὲν αὐτοῦ τὴν εἰς τἀληθὲς σπουδὴν, παρασχεῖν δὲ διά τινος ἀσφαλεστέρου καὶ χωρὶς αἵματος καὶ σφαγῆς, ἄλλως τε καὶ ὅτι ἱερὸν ἡγεῖτο εἶναι τὸν ἀλεκτρυόνα ἡλίῳ, τὸ λεγόμενον παναληθὲς ἀπετέλεσεν αὐτῷ δι’ ἀριθμητικῆς ἐπιστήμης συντεταγμένον.

From this, then, it has become clear that he took over from the Orphics the essence of the gods as defined by number. Through the same numbers he also practised a wonderful foreknowledge, and a worship of the gods according to the numbers, as closely akin [to them] as possible. One might learn this from the following; for some deed must also be offered as proof of what is said. When Abaris was continuing in the sacred rites customary to him, and was procuring through sacrifices the foreknowledge prized by every race of barbarians — especially through sacrifices of birds, for they consider the entrails of such creatures exact for inspection — Pythagoras, not wishing to take away his zeal for the truth, but to provide it to him through some safer means, without blood and slaughter, and especially also because he held the cock to be sacred to the Sun, accomplished for him what is called the 'all-true', composed by arithmetical science.