The Nicene Creed and Its Anathemas
Athanasius is writing to the emperor Jovian, explaining that those corrupted by the Arian heresy now oppose the true faith, and he is about to quote the creed confessed at Nicaea.
For those men, having been harmed over a long time by the Arian heresy, now oppose true religion more contentiously. And so that your piety may know it—though it already does—I have been eager to set down the faith confessed at Nicaea by the bishops. The faith confessed by the Fathers at Nicaea is this: We believe in one God, the Father almighty, maker of all things visible and invisible; and in one Lord Jesus Christ, the Son of God, begotten from the Father, only-begotten, that is, from the essence of the Father, God from God, light from light, true God from true God, begotten, not made, of one being with the Father, through whom all things came to be, both in heaven and on earth; who for us human beings and for our salvation came down, became flesh, became human, suffered, rose on the third day, ascended into heaven, and is coming to judge the living and the dead; and in the Holy Spirit. But those who say, 'There was a time when he was not,' and 'Before being begotten he was not,' and that he came to be from nothing, or who say that the Son of God is from another substance or essence, or that he is created, or changeable, or alterable—these the catholic and apostolic Church anathematizes. It is necessary, Augustus, for all to hold fast to this faith as divine and apostolic, and for no one to shift it by persuasive arguments and word-battles, which is what the followers of Arius have done, saying that the Son of God is from nothing, and that there was a time when he was not, and that he is created, a thing made, and changeable. For this reason, as I said before, the council at Nicaea anathematized that heresy and confessed the faith of the truth. They did not simply say that the Son is like the Father, so that he would not be believed to be merely like God but true God from God; rather, they wrote 'of one being,' which is proper to a genuine and true Son, true and by nature from the Father. Nor did they alienate the Holy Spirit from the Father and the Son, but rather glorified it with the Father and the Son in the one faith of the Holy Trinity, because there is one divinity in the Holy Trinity.
Greek
Ἐκεῖνοι γὰρ, πολλῷ χρόνῳ βλαβέντες ἀπὸ τῆς Ἀρειανῆς αἱρέσεως, φιλονεικότερον ἀνθίστανται νῦν τῇ εὐσεβείᾳ. Καὶ ὑπὲρ τοῦ γινώσκειν τὴν σὴν εὐσέβειαν, καίτοι γινώσκουσαν, ὅμως ἐσπουδάσαμεν τὴν ἐν Νικαίᾳ πίστιν ὁμολογηθεῖσαν ὑπὸ τῶν ἐπισκόπων ὑποτάξαι. Ἔστι μὲν οὖν ἡ παρὰ τῶν Πατέρων ὁμολογηθεῖσα πίστις ἐν Νικαίᾳ αὕτη· Πιστεύομεν εἰς ἕνα Θεὸν, Πατέρα παντοκράτορα, πάντων ὁρατῶν τε καὶ ἀοράτων ποιητήν· καὶ εἰς τὸν ἕνα Κύριον Ἰησοῦν Χριστὸν, τὸν Υἱὸν τοῦ Θεοῦ, γεννηθέντα ἐκ τοῦ Πατρὸς μονογενῆ, τουτέστιν ἐκ τῆς οὐσίας τοῦ Πατρὸς, Θεὸν ἐκ Θεοῦ, φῶς ἐκ φωτὸς, Θεὸν ἀληθινὸν ἐκ Θεοῦ ἀληθινοῦ, γεννηθέντα, οὐ ποιηθέντα, ὁμοούσιον τῷ Πατρὶ, δι' οὗ τὰ πάντα ἐγένετο, τά τε ἐν τῷ οὐρανῷ καὶ τὰ ἐπὶ τῆς γῆς· τὸν δι' ἡμᾶς τοὺς ἀνθρώπους καὶ διὰ τὴν ἡμετέραν σωτηρίαν κατελθόντα, καὶ σαρκωθέντα, ἐνανθρωπήσαντα, παθόντα, καὶ ἀναστάντα τῇ τρίτῃ ἡμέρᾳ, καὶ ἀνελθόντα εἰς τοὺς οὐρανοὺς, ἐρχόμενον κρῖναι ζῶντας καὶ νεκρούς· καὶ εἰς τὸ Πνεῦμα τὸ ἅγιον. Τοὺς δὲ λέγοντας, Ἦν ποτε, ὅτε οὐκ ἦν, καὶ, Πρὶν γενηθῆναι, οὐκ ἦν, καὶ ὅτι Ἐξ οὐκ ὄντων ἐγένετο, ἢ ἐξ ἑτέρας ὑποστάσεως ἢ οὐσίας φάσκοντας εἶναι, ἢ κτιστὸν, ἢ τρεπτὸν, ἢ ἀλλοιωτὸν τὸν Υἱὸν τοῦ Θεοῦ, τούτους ἀναθεματίζει ἡ καθολικὴ καὶ ἀποστολικὴ Ἐκκλησία. Ταύτῃ τῇ πίστει, Αὔγουστε, πάντας ἐπιμένειν ἀναγκαῖον, ὡς θείᾳ καὶ ἀποστολικῇ, καὶ μηδένα μετακινεῖν αὐτὴν πιθανολογίαις καὶ λογομαχίαις, ὅπερ πεποιήκασιν οἱ Ἀρειομανῖται, ἐξ οὐκ ὄντων τὸν Υἱὸν τοῦ Θεοῦ λέγοντες, καὶ ὅτι ἦν ποτε ὅτε οὐκ ἦν, καὶ κτιστὸς, καὶ ποιητὸς, καὶ τρεπτός ἐστι. Διὰ τοῦτο γὰρ, καθὰ προείπομεν, καὶ ἡ ἐν Νικαίᾳ σύνοδος ἀνεθεμάτισε τὴν τοιαύτην αἵρεσιν, τὴν δὲ τῆς ἀληθείας πίστιν ὡμολόγησεν. Οὐ γὰρ ἁπλῶς ὅμοιον εἰρήκασι τὸν Υἱὸν τῷ Πατρὶ, ἵνα μὴ ἁπλῶς ὅμοιος Θεῷ, ἀλλ' ἐκ Θεοῦ Θεὸς ἀληθινὸς πιστεύηται· ἀλλ' ὁμοούσιος ἔγραψαν, ὅπερ ἴδιον ἦν γνησίου καὶ ἀληθινοῦ Υἱοῦ, ἀληθινοῦ καὶ φύσει τοῦ Πατρός. Ἀλλ' οὐδὲ ἀπηλλοτρίωσαν τὸ Πνεῦμα τὸ ἅγιον ἀπὸ τοῦ Πατρὸς καὶ τοῦ Υἱοῦ, ἀλλὰ μᾶλλον συνεδόξασαν αὐτὸ τῷ Πατρὶ καὶ τῷ Υἱῷ ἐν τῇ μιᾷ τῆς ἁγίας Τριάδος πίστει, διὰ τὸ καὶ μίαν εἶναι ἐν τῇ ἁγίᾳ Τριάδι θεότητα.