The Holy Canons Apostolic Canon 68
Canon 68 No second ordination, unless the first was heretical
Ἱεροὶ Κανόνες τῶν Ἁγίων καὶ Πανσέπτων Ἀποστόλων
The Apostolic Canons · compiled in Syria in the later fourth century · The Apostolic Canons on the map
If any bishop, or presbyter, or deacon receives a second ordination from anyone, let him be deposed, both he and the one who ordained him; unless indeed it be established that he has his ordination from heretics. For those who have been baptised or ordained by such can be neither faithful nor clerics.
Εἴ τις ἐπίσκοπος, ἢ πρεσβύτερος, ἢ διάκονος, δευτέραν χειροτονίαν δέξηται παρά τινος, καθαιρείσθω καὶ αὐτός, καὶ ὁ χειροτονήσας· εἰ μή γε ἄρα συσταίη, ὅτι παρὰ αἱρετικῶν ἔχει τὴν χειροτονίαν. Τοὺς γὰρ παρὰ τῶν τοιούτων βαπτισθέντας ἢ χειροτονηθέντας, οὔτε πιστούς, οὔτε κληρικοὺς εἶναι δυνατόν.
The Apostolic Canons, 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.