Peter's Error

Καὶ προσλαβόμενος αὐτὸν Πέτρος, ἤρχατο ἐπιτιμᾷν αὐτῷ, λέγων· Ἴλεώς σοι, Κύριε, οὐ μὴ ἔσται σοι τοῦτο. Ὅ μὲν ἀπεκαλύφθη, ὁ Πέτρος ὀρθῶς ὡμολόγησεν, ὃ δὲ οὐκ ἀπεκαλύφθη, ἐσφάλη· ἵνα μάθων ὅτι χωρὶς Θεοῦ οὐδὲ ἐκεῖνο ἐφθέγξατο τὸ μέγα. Μὴ θέλων οὖν παθεῖν τὸν Χριστὸν ὁ Πέτρος, καὶ ἀγνοῶν τὸ τῆς ἀναστὰσεωη μυστήριον· Ἴλεώς σοι, Κύριε, οὐ μὴ ἔσται σοι τοῦτο φησίν. Ὁ δὲ στραφεὶς εἴπε τῷ Πέτρῳ· Ὕπαγε ὀπίσω μου, Σατανᾶ, σκάνδαλόν μου εἴ, ὅτι οὐ φρονεῖς τὰ τοῦ Θεοῦ, ἀλλὰ τὰ τῶν ἀνθρώπων. Ὅτε μὲν ὀρθὰ ἐλάλει ὁ Πέτρος, μακαρίζει αὐτὸν ὁ Χριστὸς, ὅτε δὲ ἀλόγως ἐδειλίασε, καὶ οὐκ ἤθελε παθεῖν αὐτὸν, ἐπέπληξεν, εἰπων· Ὕπαγε οὖν ὀπισω μου, Σατανᾶ. Σατανᾶς δὲ, ἀντικείμενος λέγεται. Ὕπαγε οὖν ὀπισω μου, τουτέστι, μὴ ἀνθίστασο, ἀλλ' ἀκολούθει τῷ θελήματί μου. Καλεῖ δὲ οὕτως τὸν Πέτρον, ἐπεὶ καὶ τῷ Σατανᾷ ἀθέλητον ἦν τὸ παθεῖν τὸν Χριστόν· φησιν οὖν ὅτι, Συ μὲν ἀνθρωπίνῳ λογισμῷ δοκεῖς τὸ πάθος ἀπρεπές μοι εἶναι· οὐ νοεῖς δὲ ὅτι ὁ Θεὸς διὰ τούτου σωτηρίαν ἐργάζεται, καί ὅτι τοῦτο ἐμοὶ πρέπει μάλιστα. Θεοφύλακτος Αχρίδος, Ἑρμηνεία Εἰς Τὸ Κατά Ματθαίον Εὐαγγέλιον, Κεφ' Ιϛ' Source: Migne PG 123.321b-c

And seizing Him Peter began to berate him, saying. 'May this never happen to you, Lord.' 1 That which was revealed, Peter rightly confessed, 2 but he erred in what was not revealed, that we might know that without God no speech can be great. Therefore Peter did not want Christ to suffer, and ignorant of the mystery of the resurrection said, 'May this never happen to you, Lord.' And turning to Him, He said to Peter: 'Get behind me Satan, you are a scandal to me, because you do not know the things of God but the things of men.' When Peter spoke rightly, the Lord blessed him, 2 but when he was confused by fear and unwilling that He should suffer, He rebuked him, saying: 'Get behind me, Satan.' And he is named Satan as an adversary. Therefore 'Get behind me,' means 'do not obstruct me, but follow my will.' So he spoke to Peter, because even Satan was displeased by the suffering of Christ. Therefore He says: 'According to human reasoning my passion appears shameful to you, but you do not understand that God works salvation through this, so that this befits me very much.' Theophylact of Ochrid, Commentary On The Gospel Of Saint Matthew, Chapter 16 1 Mt 16.22 2 Mt 16.16-17