Why brevity sufficed against Marcellus
Eusebius opens his letter to Flacillus by explaining why his short reply to Marcellus' wordy treatise was enough.
If our brief response sufficed against Marcellus' babbling, wordy treatise, there is no need to wonder. For no lengthy arguments were needed to refute things condemned on the spot even by ordinary people. Therefore, in the first two books I used only the quotation of the man's words, without any counter-argument, and made the exposure against them evident from the words themselves. Now, in addition to that exposure, I have also brought forward the refutation of the same points through the three books at hand. For he composed one enormous, much-wandering treatise and says he did this because he makes one God known, dividing the treatise so that it might not somehow escape him to give the Son of God room for a distinct person. But we, honoring the all-holy and thrice-blessed Trinity, have gathered the whole subject into these few books, sparing lengthy speech and presenting the true theology concisely and briefly. If, then, what has been written is sufficient, you yourself may judge as you read. But if anything is lacking, you may fill these gaps too—clearly, as a brother would supply a brother's deficiencies—making up for it through correction wherever healing may be needed. I pray that you fare well and remember me before the Lord always.
Greek
Εἰ πρὸς τὴν ἀδόλεσχον καὶ πολυεπῆ Μαρκέλλου γραφὴν τὰ παρ’ ἡμῶν ἐν βραχέσιν ἤρκεσεν, οὐ χρὴ θαυμάζειν· οὐ γὰρ δὴ πολλῶν ἔδει λόγων πρὸς ἀνατροπὴν τῶν αὐτόθεν καὶ τοῖς τυχοῦσιν κατεγνωσμένων. διὸ δὴ ἐν δυσὶ τοῖς πρώτοις μόνῃ τῇ παραθέσει τῶν τοῦ ἀνδρὸς ῥημάτων χρησάμενος δίχα πάσης ἀντιρρήσεως ἐξ αὐτῶν τὸν κατ’ αὐτῶν ἔλεγχον φανερὸν ἐποιούμην. νυνὶ δὲ πρὸς ἐκείνῃ τῇ φώρᾳ καὶ τὴν ἀνατροπὴν τῶν αὐτῶν διὰ τριῶν τῶν μετὰ χεῖρας προσήγαγον. ὁ μὲν γὰρ ἕν τι διωλύγιον καὶ πολυπλανὲς σύγγραμμα συντάξας τοῦτό φησιν πεποιηκέναι διὰ τὸ ἕνα γνωρίζειν θεόν, μή πη λάθῃ τῷ υἱῷ τοῦ θεοῦ χώραν διδοὺς ὑποστάσεως διελὼν τὴν γραφήν. ἡμεῖς δὲ τὴν παναγίαν καὶ τρισμακαρίαν τιμῶντες τριάδα ἐν τοσούτοις τὴν πᾶσαν ὑπόθεσιν συνειλήφαμεν, φεισάμενοι μὲν πολυλογίας, ἐν ἐπιτόμοις δὲ καὶ βραχέσιν τὴν ἀληθῆ παραστήσαντες θεολογίαν. εἰ μὲν οὖν αὐταρκῶς ἔχει τὰ γραφέντα, κρίνειας ἂν αὐτὸς ἐντυγχάνων· εἰ δέ τινα λείποι, καὶ ταῦτα 〈ἂν〉 ἀναπληρώσειας, δηλαδὴ [ἃ δὴ] ἀδελφὸς ἀδελφοῦ τὰ ὑστερήματα, εἴ που καὶ θεραπείας δέοιτο, δι’ ἐπανορθώσεως ἐξιώμενος.
Ἔρρωσθαί σε καὶ μνημονεύειν μου τῷ κυρίῳ διὰ παντὸς εὔχομαι.