Everything that is contrary to right reason is sin. Accordingly, therefore, the philosophers think fit to define the most generic passions thus: lust, as desire disobedient to reason; fear, as weakness disobedient to reason; pleasure, as an elation of the spirit disobedient to reason. If, then, disobedience in reference to reason is the generating cause of sin, how shall we escape the conclusion, that obedience to reason—the Word—which we call faith, will of necessity be the efficacious cause of duty? For virtue itself is a state of the soul rendered harmonious by reason in respect to the whole life. Nay, to crown all, philosophy itself is pronounced to be the cultivation of right reason; so that, necessarily, whatever is done through error of reason is transgression, and is rightly called, (ἁμάρτημα) sin. Since, then, the first man sinned and disobeyed God, it is said, “And man became like to the beasts:”266 Ps. xlix. 12, 20. being rightly regarded as irrational, he is likened to the beasts. Whence Wisdom says: “The horse for covering; the libidinous and the adulterer is become like to an irrational beast.”267 Ecclus. xxxiii. 6. Wherefore also it is added: “He neighs, whoever may be sitting on him.” The man, it is meant, no longer speaks; for he who transgresses against reason is no longer rational, but an irrational animal, given up to lusts by which he is ridden (as a horse by his rider).
But that which is done right, in obedience to reason, the followers of the Stoics call προσῆκον and καθῆκον, that is, incumbent and fitting. What is fitting is incumbent. And obedience is founded on commands. And these being, as they are, the same as counsel—having truth for their aim, train up to the ultimate goal of aspiration, which is conceived of as the end (τέλος). And the end of piety is eternal rest in God. And the beginning of eternity is our end. The right operation of piety perfects duty by works; whence, according to just reasoning, duties consist in actions, not in sayings. And Christian conduct is the operation of the rational soul in accordance with a correct judgment and aspiration after the truth, which attains its destined end through the body, the soul’s consort and ally.268 [Note this definition in Christian ethics.] Virtue is a will in conformity to God and Christ in life, rightly adjusted to life everlasting. For the life of Christians, in which we are now trained, is a system of reasonable actions—that is, of those things taught by the Word—an unfailing energy which we have called faith. The system is the commandments of the Lord, which, being divine statutes and spiritual counsels, have been written for ourselves, being adapted for ourselves and our neighbours. Moreover, they turn back on us, as the ball rebounds on him that throws it by the repercussion. Whence also duties are essential for divine discipline, as being enjoined by God, and furnished for our salvation. And since, of those things which are necessary, some relate only to life here, and others, which relate to the blessed life yonder, wing us for flight hence; so, in an analogous manner, of duties, some are ordained with reference to life, others for the blessed life. The commandments issued with respect to natural life are published to the multitude; but those that are suited for living well, and from which eternal life springs, we have to consider, as in a sketch, as we read them out of the Scriptures.
Ὅτι ὡς τὸ κατόρθωμα κατὰ τὸν ὀρθὸν γίνεται λόγον, οὕτως ἔμπαλιν τὸ ἁμάρτημα παρὰ τὸν λόγον. Πᾶν τὸ παρὰ τὸν λόγον τὸν ὀρθὸν τοῦτο ἁμάρτημά ἐστιν. Αὐτίκα γοῦν τὰ πάθη τὰ γενικώτατα ὧδέ πως ὁρίζεσθαι ἀξιοῦσιν οἱ φιλόσοφοι, τὴν μὲν ἐπιθυμίαν ὄρεξιν ἀπειθῆ λόγῳ, τὸν δὲ φόβον ἔκκλισιν ἀπειθῆ λόγῳ, ἡδονὴν δὲ ἔπαρσιν ψυχῆς ἀπειθῆ λόγῳ, λύπην δὲ συστολὴν ψυχῆς ἀπειθῆ λόγῳ. Εἰ τοίνυν ἡ πρὸς τὸν λόγον ἀπείθεια ἁμαρτίας ἐστὶ γεννητική, πῶς οὐχὶ ἐξ ἀνάγκης ἡ τοῦ λόγου ὑπακοή, ἣν δὴ πίστιν φαμέν, τοῦ καλουμένου καθήκοντος ἔσται περιποιητική; Καὶ γὰρ ἡ ἀρετὴ αὐτὴ διάθεσίς ἐστι ψυχῆς σύμφωνος τῷ λόγῳ περὶ ὅλον τὸν βίον. Ναὶ μὴν τὸ κορυφαιότατον, αὐτὴν φιλοσοφίαν ἐπιτήδευσιν λόγου ὀρθότητος ἀποδιδόασιν, ὡς ἐξ ἀνάγκης εἶναι τὸ πλημμελούμενον πᾶν διὰ τὴν τοῦ λόγου διαμαρτίαν γινόμε νον εἰκότως καλεῖσθαι ἁμάρτημα. Αὐτίκα γοῦν ὅτε ἥμαρτεν ὁ πρῶτος ἄνθρωπος καὶ παρήκουσεν τοῦ θεοῦ, καὶ παρωμοιώθη, φησί, τοῖς κτήνεσιν. Ὁ ἄνθρωπος παρὰ τὸν λόγον ἐξαμαρτὼν εἰκότως ἄλογος νομισθεὶς εἰκάζεται κτήνεσιν. Ἐντεῦθεν καὶ ἡ σοφία λέγει· ἵππος εἰς ὀχείαν ὁ φιλήδονος καὶ ὁ μοιχός, ἀλογίστῳ κτήνει παρομοιωθείς, διὸ καὶ ἐπιφέρει· παντὸς ὑποκάτω ἐπικαθημένου χρεμετίζει. Οὐκέτι λαλεῖ, φησίν, ὁ ἄνθρωπος· οὐ γάρ ἐστιν λογικὸς ἔτι ὁ παρὰ λόγον ἁμαρτάνων, θηρίον δὲ δὴ ἄλογον, ἔκδοτον ἐπιθυμίαις, ᾧ πᾶσαι ἐπικάθηνται ἡδοναί. Τὸ δὲ κατορθούμενον κατὰ τὴν τοῦ λόγου ὑπακοὴν προσῆκον καὶ καθῆκον Στωϊκῶν ὀνομάζουσιν παῖδες· τὸ μὲν οὖν καθῆκον προσῆκόν ἐστιν, ὑπακοὴ δὲ θεμελιοῦται ἐντολαῖς· αὗται δὲ ταῖς ὑποθήκαις αἱ αὐταὶ οὖσαι τὴν ἀλήθειαν ἔχουσαι σκοπόν, ἐπὶ τὸ ἔσχατον ὀρεκτόν, ὃ τέλος νοεῖται, παιδαγωγοῦσιν· τέλος δέ ἐστιν θεοσεβείας ἡ ἀίδιος ἀνάπαυσις ἐν τῷ θεῷ, τοῦ δὲ αἰῶνός ἐστιν ἀρχὴ τὸ ἡμέτερον τέλος. Τὸ μέντοι τῆς θεοσεβείας κατόρθωμα δι' ἔργων τὸ καθῆκον ἐκτελεῖ· ὅθεν εἰκότως τὰ καθήκοντα περὶ τὰς πράξεις, οὐ τὰς λέξεις, συνίσταται· καὶ ἔστιν ἡ μὲν πρᾶξις ἡ τοῦ Χριστιανοῦ ψυχῆς ἐνέργεια λογικῆς κατὰ κρίσιν ἀστείαν καὶ ὄρεξιν ἀληθείας διὰ τοῦ συμφυοῦς καὶ συναγωνιστοῦ σώματος ἐκτελουμένη· καθῆκον δὲ ἀκόλουθον ἐν βίῳ θεῷ καὶ Χριστῷ βούλημα ἕν, κατορθούμενον ἀιδίῳ ζωῇ· καὶ γὰρ ὁ βίος ὁ Χριστιανῶν, ὃν παιδαγωγούμεθα νῦν, σύστημά τί ἐστι λογικῶν πράξεων, τουτέστιν τῶν ὑπὸ τοῦ λόγου διδασκομένων ἀδιάπτω τος ἐνέργεια, ἣν δὴ πίστιν κεκλήκαμεν. Τὸ δὲ σύστημα ἐντολαὶ κυριακαί, αἳ δὴ δόξαι οὖσαι θεϊκαὶ ὑποθῆκαι πνευματικαὶ ἡμῖν αὐτοῖς ἀναγεγράφαται, πρός τε ἡμᾶς αὐτοὺς καὶ πρὸς τοὺς πέλας εὔθετοι· καὶ δὴ καὶ αὗται αὖθις πρὸς ἡμᾶς ἀνταναστρέφουσι, καθάπερ πρὸς τὸν βάλλοντα ἡ σφαῖρα διὰ τὴν ἀντιτυπίαν παλινδρομοῦσα· ὅθεν καὶ ἔστιν ἀναγκαῖα τὰ καθήκοντα εἰς παιδαγωγίαν θεϊκήν, ὡς ὑπὸ θεοῦ παρηγγελμένα καὶ εἰς σωτηρίαν πεπορισμένα. Καὶ ἐπεὶ τῶν ἀναγκαίων τὰ μὲν πρὸς τὸ ζῆν ἐστι τὸ ἐνταῦθα μόνον, τὰ δὲ ἔνθεν πρὸς τὸ εὖ ζῆν ἐκεῖσε ἀναπτεροῖ, ἀναλόγως καὶ τῶν καθηκόντων τὰ μὲν πρὸς τὸ ζῆν, τὰ δὲ πρὸς τὸ εὖ ζῆν διατάττεται. Ὅσα μὲν οὖν πρὸς τὸ ἐθνικὸν ζῆν παραγγέλλεται, ταῦτα καὶ παρὰ τοῖς πολλοῖς δεδήμευται, ἃ δὲ πρὸς τὸ εὖ ζῆν ἁρμόττει, ἐξ ὧν τὸ ἀίδιον ἐκεῖνο περιγίνεται ζῆν, ταῦτα δὲ ἐν ὑπογραφῆς μέρει ἐξ αὐτῶν ἀναλεγομένοις τῶν γραφῶν ἐξέστω σκοπεῖν.