Letter 1084: Virtue must be practiced with all one's strength — not merely admired from a distance.

To Didymus. Those who err glaringly in what is acknowledged by all would hardly be credible when they pronounce upon what seems open to dispute. For if it is not lawful for those who embrace vice even to raise a discussion about the divine ordinances - for to the sinner God said, "Why do you declare my ordinances?" [Psalm 49:16, Septuagint numbering] - how is it lawful for those who, by the very things they do, outrage those same ordinances, to argue about doctrines? If, therefore, virtue is the guarantee of piety, one must be zealous to possess it, since through it piety will be declared trustworthy. For no one will be persuaded by a man who does not live well, since his vice both outrages sound doctrines and does not allow them to be received. Virtue and piety, then, must be held fast: the one is the foundation, the other the crown and adornment. Both, therefore, must be retained with equal zeal, the one being the foundation, the other the crown. [the final sentence is given in Latin in the source, restating the Greek]

Οἱ περὶ τὸ (85) ὁμολογούμενον (86) λαμπρῶς πταίοντες, οὐκ ἄν εἶεν ἀξιόχρεῳ περὶ τοῦ δοκοῦντος ἀμφισβητησίμου ἀποφαινόμενοι. Εἰ γὰρ τοῖς κακίαν ἀσπαζομένοις, οὐδὲ περὶ τῶν θείων δικαιωμάτων λόγον κινεῖν θέμις· « Τῷ γὰρ ἁμαρτωλῷ εἶπεν ὁ Θεός· Ἵνα τί σὺ ἐκδιηγῇ τὰ δικαιώματά μου; » πῶς τοῖς καὐτὰ τὰ δικαιώματα δι' ὧν πράττουσιν ὑβρίζουσι περὶ δογμάτων διαλέγεσθαι θέμις; Εἰ τοίνυν ἡ ἀρετὴ τὴν εὐσέβειαν ἐγγυᾶται, σπουδαστέον αὐτὴν ἔχειν, δι' ἣν ἡ εὐσέβεια ἀξιόχρεως ἀποφανθήσεται. Τῷ γὰρ οὐκ εὖ βιούντι οὐδεὶς πεισθήσεται, τῆς κακίας καὶ τὰ ὀρθὰ καθυβριζούσης δόγματα, καὶ καταδεχθῆναι (87) μὴ συγχωρούσης. Ἀρετῆς τοίνυν καὶ εὐσεβείας ἀνθεκτέον· ὡς ἡ μὲν θεμέλιός ἐστιν, ἡ δὲ στεφάνη καὶ ἐγκαλλώπισμα. Utrumque igitur pari studio retinendum est, quorum alterum sit fundamentum, alterum corona.