Canon 18
Against church conspiracies and “forming crowds” (malicious meetings).
Conspiracy or the formation of secret societies, as a crime, is completely prohibited by external laws, all the more so it should be prohibited from being in the Church of God. So, if it turns out that any clergy or monastics are conspiring, or forming secret societies, or plotting intrigues against bishops or fellow clerics, let them be completely deprived of their rank.
Greek original
Τὸ τῆς συνωμοσίας, ἢ φατρίας, ἔγκλημα καὶ παρὰ τῶν ἔξω νόμων πάντῃ κεκώλυται, πολλῷ δὴ μᾶλλον ἐν τῇ τοῦ Θεοῦ ἐκκλησίᾳ τοῦτο γίνεσθαι ἀπαγορεύειν προσήκει. Εἴ τινες τοίνυν κληρικοί, ἢ μονάζοντες, εὑρεθεῖεν συνομνύμενοι, ἢ φατριάζοντες, ἢ κατασκευὰς τυρεύοντες ἐπισκόποις, ἢ συγκληρικοῖς, ἐκπιπτέτωσαν πάντῃ τοῦ οἰκείου βαθμοῦ.
Parallel canons
Ап.31IIВс.6IIIВс.3Трул.3134Гангр.6Сард.14Антиох.5Карф.1011Двукр.13