Canon 16 Clergy who leave their church must not be received

Κανόνες τῆς ἐν Νικαίᾳ Ἁγίας καὶ Οἰκουμενικῆς Α´ Συνόδου

The First Ecumenical Council · Nicaea, 325 · convened by the emperor Constantine · First Ecumenical Council: Nicaea I (325) on the map

As many as recklessly, neither having the fear of God before their eyes nor knowing the ecclesiastical canon, withdraw from their own church, presbyters, or deacons, or in general those reckoned in the canon, these ought by no means to be received in another church; but every compulsion must be brought to bear on them to return to their own dioceses; or, if they persist, it is fitting that they be out of communion. And if anyone should even dare to snatch away one who belongs to another, and to ordain him in his own church, without the consent of the man's own bishop, from whom the one reckoned in the canon withdrew, let the ordination be void.

Ὅσοι ῥιψοκινδύνως, μήτε τὸν φόβον τοῦ Θεοῦ πρὸ ὀφθαλμῶν ἔχοντες, μήτε τὸν ἐκκλησιαστικὸν κανόνα εἰδότες, ἀναχωρήσωσι τῆς ἰδίας ἐκκλησίας, πρεσβύτεροι, ἢ διάκονοι, ἢ ὅλως ἐν τῷ κανόνι ἐξεταζόμενοι, οὗτοι οὐδαμῶς δεκτοὶ ὀφείλουσιν εἶναι ἐν ἑτέρᾳ ἐκκλησίᾳ· ἀλλὰ πᾶσαν αὐτοῖς ἀνάγκην ἐπάγεσθαι χρή, ἀναστρέφειν εἰς τὰς ἑαυτῶν παροικίας· ἤ, ἐπιμένοντας, ἀκοινωνήτους εἶναι προσήκει. Εἰ δὲ καὶ τολμήσειέ τις ὑφαρπάσαι τὸν τῷ ἑτέρῳ διαφέροντα, καὶ χειροτονῆσαι ἐν τῇ αὑτοῦ ἐκκλησίᾳ, μὴ συγκατατιθεμένου τοῦ ἰδίου ἐπισκόπου, οὗ ἀνεχώρησεν ὁ ἐν τῷ κανόνι ἐξεταζόμενος, ἄκυρος ἔστω ἡ χειροτονία.

The First Ecumenical Council, the canons

English: this site's translation of the Greek beside it. Greek: the text of the Pedalion, as transcribed at users.uoa.gr/~nektar and corrected here. About these texts.