Καὶ ἡ τροφὴ αὕτη καλεῖται παρ’ ἡμῖν εὐχαριστία, ἧς οὐδενὶ ἄλλῳ μετασχεῖν ἐξόν ἐστιν ἢ τῷ πιστεύοντι ἀληθῆ εἶναι τὰ δεδιδαγμένα ὑφ’ ἡμῶν, καὶ λουσαμένῳ τὸ ὑπὲρ ἀφέσεως ἁμαρτιῶν καὶ εἰς ἀναγέννησιν λουτρόν, καὶ οὕτως βιοῦντι ὡς ὁ Χριστὸς παρέδωκεν. οὐ γὰρ ὡς κοινὸν ἄρτον οὐδὲ κοινὸν πόμα ταῦτα λαμβάνομεν· ἀλλ’ ὃν τρόπον διὰ λόγου θεοῦ σαρκοποιηθεὶς Ἰησοῦς Χριστὸς ὁ σωτὴρ ἡμῶν καὶ σάρκα καὶ αἷμα ὑπὲρ σωτηρίας ἡμῶν ἔσχεν, οὕτως καὶ τὴν δι’ εὐχῆς λόγου τοῦ παρ’ αὐτοῦ εὐχαριστηθεῖσαν τροφήν, ἐξ ἧς αἷμα καὶ σάρκες κατὰ μεταβολὴν τρέφονται ἡμῶν, ἐκείνου τοῦ σαρκοποιηθέντος Ἰησοῦ καὶ σάρκα καὶ αἷμα ἐδιδάχθημεν εἶναι. οἱ γὰρ ἀπόστολοι ἐν τοῖς γενομένοις ὑπ’ αὐτῶν ἀπομνημονεύμασιν, ἃ καλεῖται εὐαγγέλια, οὕτως παρέδωκαν ἐντετάλθαι αὐτοῖς· τὸν Ἰησοῦν λαβόντα ἄρτον εὐχαριστήσαντα εἰπεῖν· Τοῦτο ποιεῖτε εἰς τὴν ἀνάμνησίν μου, τοῦτ’ ἐστι τὸ σῶμά μου· καὶ τὸ ποτήριον ὁμοίως λαβόντα καὶ εὐχαριστήσαντα εἰπεῖν· Τοῦτό ἐστι τὸ αἷμά μου· καὶ μόνοις αὐτοῖς μεταδοῦναι. ὅπερ καὶ ἐν τοῖς τοῦ Μίθρα μυστηρίοις παρέδωκαν γίνεσθαι μιμησάμενοι οἱ πονηροὶ δαίμονες· ὅτι γὰρ ἄρτος καὶ ποτήριον ὕδατος τίθεται ἐν ταῖς τοῦ μυουμένου τελεταῖς μετ’ ἐπιλόγων τινῶν, ἢ ἐπίστασθε ἢ μαθεῖν δύνασθε.
(Justin Martyr, 1 Apol. 66)
And this food is called among us Εὐχαριστία [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Saviour, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, This do in remembrance of Me, [Luke 22:19] this is My body; and that, after the same manner, having taken the cup and given thanks, He said, This is My blood; and gave it to them alone. Which the wicked devils have imitated in the mysteries of Mithras, commanding the same thing to be done. For, that bread and a cup of water are placed with certain incantations in the mystic rites of one who is being initiated, you either know or can learn. (tr. Marcus Dods & George Reith)