Letter 1109: The spiritual life is a journey with a beginning, a middle, and an end.

To Nemesios. On the text, "All that the Lord has said we will do and we will hear" [Exodus 24:7]; and on the text, "The natural man does not receive the things of the Spirit" [1 Corinthians 2:14]; and on the text, "A bad tree cannot bear good fruit" [Matthew 7:18]. You perhaps think the saying strange, since it was spoken by the Jews, who neither say nor do anything right. But I, since the Lawgiver did not blame them for this, hold that what one must learn in order to do, this we learn through the very doing. For this reason it is well said, "All that the Lord has said we will do and we will hear." For those who are learning some other thing reasonably first hear, and the proofs are present to them; but those who are to carry the divine commandments into action learn first of all from the practice, not from a clever account, inasmuch as the practice gives birth to the knowledge. For in truth the exercise of virtue is instructed in virtue through the very exercise, and in a certain way learns that it is most useful, most fitting, and most preservative, and that it has been laid down as law to our advantage. And concerning this, enough. Now as for "A bad tree cannot bear good fruit" — this does not abolish repentance, but rather holds up to ridicule persistence in dwelling upon wickedness. For being bad, it cannot bring forth good fruits; but once changed into virtue, it will bear them. For if the Savior's word were about trees, let your argument prevail; but if it is about human beings, and He used an illustration (for what nature is to those trees, this our free choice is to us), then let the supposition be overturned. For what sort of tree does Peter seem to you to be? A good one. And how then did he deny [Christ]? A bad one. And how then does all land and sea sing his contests and his trophies? And what sort was Judas? A bad one. And how then was he counted worthy of the apostolic honor? A good one. And how then did he betray? But if I were to bring forward into the midst all the transformations that have taken place among human beings, I would unknowingly introduce a multitude of words. Therefore I will allow you to gather those examples for yourself from the Scriptures, since I am pressing on toward the interpretation of the apostolic saying. "The natural man," even if he does not receive the things of the Spirit, yet he will receive them; for he did not say, "He will not receive," but, "He does not receive." And again, "He cannot know" — and he did not say, "He will not be able." For just as if something is by nature hard like iron, and one were to say, "It cannot be cold," yet it will be able to be; so also in the case of the things spoken: the one belongs to the present time, the other to the future.

Εἰς τὸ, «Πάντα, ὅσα ἂν εἶπεν ὁ Κύριος, ποιήσομεν, καὶ ἀκουσόμεθα (58*)». Καὶ εἰς τὸ, «Ὁ ψυχικὸς ἄνθρωπος οὐ δέχεται τὰ τοῦ πνεύματος». Καὶ εἰς τὸ, «Οὐ δύναται δένδρον πονηρὸν καρποὺς καλοὺς ποιεῖν». Σὺ μὲν ἴσως ἀλλόκοτον νομίζεις τὴν φωνὴν, ἅτε παρὰ Ἰουδαίων, τῶν μηδὲν ὀρθὸν μήτε λεγόντων μήτε πραττόντων, ῥηθεῖσαν ἐγὼ δὲ, ἐπειδὴ ὁ νομοθέτης αὐτοὺς εἰς τοῦτο οὐ κατεμέμφατο, ἡγοῦμαι, ὅτι (59) & χρὴ μανθάνοντας πράττειν, ταῦτα διὰ τοῦ Ἀ πράττειν μανθάνομεν, διὰ τοῦτο εὖ εἴρηται· «Πάντα ὁπόσα γὰρ ἄλλα τι μανθάνοντες εἰκότως ἀκούουσι, καὶ τὰς ἀποδείξεις παροῦσιν· οἱ δὲ τὰς θείας ἐντολὰς εἰς ἔργον φέρειν προηγουμένως, ἀπὸ τῆς πράξεως μανθάνουσιν, οὐκ ἀπὸ λόγου σοφοῦτον, ὅσον τῆς πράξεως τὴν γνῶσιν τικτούσης (60). Τῷ ὄντι γὰρ ἡ τῆς ἀρετῆς ἄσκησις δι’ αὐτῆς τῆς ἀσκήσεως παιδεύεται τὴν ἀρετήν, καὶ τρόπον τινὰ μανθάνει, ὅτι χρησιμωτάτη καὶ πρεπωδεστάτη καὶ φυλακτικωτάτη ἐστί, καὶ συμφερόντως νενομοθέτηται. Καὶ περὶ μὲν (61) τούτου ἅλις. Τὰ δὲ, «Οὐ δύναται δένδρον πονηρὸν καρποὺς καλοὺς ποιεῖν, ἃ ὢν τὴν μετάνοιαν ἀναιρεῖ, ἀλλὰ τὴν ἐν τῇ διατριβῇ τῆς κακίας διαμονὴν (62) κωμῳδεῖ. Πονηρὸν γὰρ ὄν, οὐ δύναται καρποὺς φέρειν ἀγαθούς· μεταβληθὲν δὲ εἰς ἀρετήν, οἴσει. Εἰ μὲν γὰρ περὶ δένδρων ἦν ὁ λόγος τῷ Σωτῆρι, κρατείτω ὁ σὸς λόγος· εἰ δὲ περὶ ἀνθρώπων, ὑποδείγματι δὲ ἐχρήσατο (ὅπερ γὰρ ἡ φύσις ἐκείνοις, ταῦθ’ ἡμῖν ἡ προαίρεσις), ἀνατρεπέσθω ἡ ὑπόνοια· ὁποῖον γάρ σοι δοκεῖ δένδρον ὁ Πέτρος; Καλόν· καὶ πῶς ἦρνήσατο; Κακόν· καὶ πῶς πᾶσα γῆ τε καὶ θάλασσα τοὺς ἄθλους αὐτοῦ ᾄδει καὶ τὰ τρόπαια; Ὁποῖον δὲ ὁ Ἰούδας; Κακόν· καὶ πῶς τῆς ἀποστολικῆς (63) ἠξιώθη τιμῆς; Καλόν· καὶ πῶς προδώκεν; Ἀλλ’ εἰ πάσας τὰς γεγενημένας μεταβολὰς ἐν ἀνθρώποις εἰς μέσον ἀγάγοιμι, λάθοιμι πλῆθος λόγων ἐπεισαγαγεῖν. Διάπερ ἐκεῖνά σοι (64) παρέξις ἀναλέξασθαι ἐκ τῶν Γραφῶν, ὅτι τὴν ἑρμηνείαν τοῦ ἀποστολικοῦ ῥητοῦ χωρήσω· «Ὁ ψυχικὸς, εἰ καὶ μὴ δέχεται τὰ τοῦ πνεύματος, ἀλλὰ δέξεταί· οὐ γὰρ εἶπεν· Οὐ δίξεται, ἀλλ’, «Οὐ δέχεται». Καὶ πάλιν· «Οὐ δύναται γνῶναι· καὶ οὐκ εἶπεν, Οὐ δυνήσεται. Ὥσπερ γὰρ εἰ τῆς σιδήρου πέφυκε σκληρόν, καὶ εἶποι· Οὐ δύναται ψυχρὸς εἶναι, δυνήσεται δέ· οὕτω καὶ ἐπὶ τῶν εἰρημένων· τὸ μὲν γὰρ ἐνεστῶτός ἐστι χρόνου, τὸ δὲ μέλλοντος.