Epictetus was a Greek Stoic Philosopher. A biography is available here: http://www.iep.utm.edu/epictetu/
He lived 55-135 A.D. His philosophical statements are useful in their own respect, and also provide a background for the intellectual climate of Apostolic and Sub-Apostolic period of the Christian Church. His positions make an interesting intellectual foil for reading the NT:
The Encheiridion was translated into Latin by Poliziano in 1497 and during the subsequent two centuries became exceptionally popular in Europe. Spanneut (1972) traces its use in monasteries in superficially Christianized form. Seventeenth-century intellectuals like Guillaume du Vair, Justus Lipsius, and Thomas Gataker generally found Epictetus’ Stoicism to be fully compatible with Christianity; see the discussion in Brooke (2006). Pascal reacted against this perception; he admired Epictetus as a moralist but regarded it as sheer arrogance to believe that the human psyche is part of the divine and can be perfected by one’s own efforts
This is from the beginning of the Discourses. 1.1-4:
Now among all the arts, none is able by itself to understand itself; none is able to test and so approve or disapprove itself. What is grammar able to do? Judge grammatical matters. Or music? Judge melodies. Which of these can actually consider itself? None. Let’s say you want to write a friend. Grammar tells you how to write, but not what to write. Likewise, when it comes to melody, music is the judge. But whether you should sing or play the guitar, music doesn’t say.
So then, what does tell us? What is able to consider itself and everything else? What else, but the power of reason. Reason alone by the power contemplation can take hold of something and say , This is its scope and how much it is worth– and all the rest.
Greek Text and Notes:
Τῶν ἄλλων δυνάμεων οὐδεμίαν εὑρήσετε αὐτὴν αὑτῆς θεωρητικήν, ουʼ τοίνυν οὐδὲ δοκιμαστικὴν ἢ ἀποδοκιμαστικήν.  ἡ γραμματικὴ μέχρι τίνος κέκτηται τὸ θεωρητικόν; μέχρι τοῦ διαγνῶναι τὰ γράμματα. ἡ μουσική; μέχρι τοῦ διαγνῶναι τὸ μέλος.  αὐτὴ οὖν αὑτὴν θεωρεῖ τις αὐτῶν; οὐδαμῶς. ἀλλʼ ὅτε μέν, ἄν τι γράφῃς τῷ ἑταίρῳ, δεῖ τούτων τῶν γραπτέων, ἡ γραμματικὴ ἐρεῖ· πότερον δὲ γραπτέον τῷ ἑταίρῳ ἢ ουʼ γραπτέον, ἡ γραμματικὴ οὐκ ἐρεῖ. καὶ περὶ τῶν μελῶν ὡσαύτως ἡ μουσική· πότερον δʼ ᾀστέον νῦν καὶ κιθαριστέον ἢ οὔτε ᾀστέον οὔτε κιθαριστέον οὐκ ἐρεῖ.  τίς οὖν ἐρεῖ; ἡ καὶ αὑτὴν θεωροῦσα καὶ τἆλλα πάντα. αὕτη δʼ ἐστὶ τίς; ἡ δύναμις ἡ λογική· μόνη γὰρ αὕτη καὶ αὑτὴν κατανοήσουσα παρείληπται, τίς τέ ἐστι καὶ τί δύναται καὶ πόσου ἀξία οὖσα ἐλήλυθεν, καὶ τὰς ἄλλας ἁπάσας
Τῶν ἄλλων δυνάμεων οὐδεμίαν εὑρήσετε αὐτὴν αὑτῆς θεωρητικήν,
Of the other abilities none you may find itself of itself it able to view/contemplate
Of the others: other than the ability he is going to discuss, below
dunamis is a power or ability. Here, Epictetus considers only intellectual pursuits; physical abilities would make no sense.
ουʼ τοίνυν οὐδὲ δοκιμαστικὴν ἢ ἀποδοκιμαστικήν.
not thus now not tested and approved or disapproved
The accusatives all follow from the primary verb “you may find”.
 ἡ γραμματικὴ μέχρι τίνος κέκτηται τὸ θεωρητικόν;
The grammar: the particular ability being discussed
until which point might it be able to contemplate?
μέχρι τοῦ διαγνῶναι τὰ γράμματα.
until the judgment of grammar
The genitive follows the preposition.
The article marks the function of the infinitive.
The accusative limits the scope of the knowledge.
ἡ μουσική; μέχρι τοῦ διαγνῶναι τὸ μέλος.
Or music until the judgment of melody
 αὐτὴ οὖν αὑτὴν θεωρεῖ τις αὐτῶν; οὐδαμῶς.
What therefore itself contemplates/looks at of itself? Nothing.
ἀλλʼ ὅτε μέν, ἄν τι γράφῃς τῷ ἑταίρῳ,
but when thus, if you were to write writing to a companion/friend
δεῖ τούτων τῶν γραπτέων, ἡ γραμματικὴ ἐρεῖ·
It is necessary of writing the grammar it says/speaks
γραπτέον, verb. Adj. of γράφω, one must describe, Xen.
2. γραπτέος, α, ον, to be described, Luc.
πότερον δὲ γραπτέον τῷ ἑταίρῳ ἢ ουʼ γραπτέον, ἡ γραμματικὴ οὐκ ἐρεῖ.
but before writing to a friend or not writing grammar does not say
καὶ περὶ τῶν μελῶν ὡσαύτως ἡ μουσική·
and cocnerning the melody likewise music
πότερον δʼ ᾀστέον νῦν καὶ κιθαριστέον ἢ οὔτε ᾀστέον οὔτε κιθαριστέον οὐκ ἐρεῖ.
but befor what one must sing now and the lyre or not to sing nor neither the lyre it does not say.
ᾀστέον, verb. Adj. of ᾄδω, one must sing, Ar., Plat.
 τίς οὖν ἐρεῖ; ἡ καὶ αὑτὴν θεωροῦσα καὶ τἆλλα πάντα.
who therefore says. or also itself contemplates and also all other things
αὕτη δʼ ἐστὶ τίς; ἡ δύναμις ἡ λογική·
By this is the ability of logic
μόνη γὰρ αὕτη καὶ αὑτὴν κατανοήσουσα παρείληπται,
for alone she and herslef contemplating receives
The participle indicates the means by which it obtains
τίς τέ ἐστι καὶ τί δύναται καὶ πόσου ἀξία οὖσα ἐλήλυθεν,
and who is and what ability and how so worthy being it has come
καὶ τὰς ἄλλας ἁπάσας
and all the other things