Правило 7
On the inadmissibility of unauthorized resignation or abandonment of monasticism.
We determined that those who had once been classified as clergy and monks should not enter into military service or secular office. And those who dare to do this and do not repent, in order to return to what was previously chosen for the sake of God, are to be anathematized.
Greek original
Τοὺς ἅπαξ ἐν κλήρῳ τεταγμένους, ἢ καὶ μοναστάς, ὡρίσαμεν μήτε ἐπὶ στρατείαν, μήτε ἐπὶ ἀξίαν κοσμικὴν ἔρχεσθαι· ἤ, τοῦτο τολμῶντας, καὶ μὴ μεταμελομένους, ὥστε ἐπιστρέψαι ἐπὶ τοῦτο, ὅ διὰ Θεὸν πρότερον εἵλοντο, ἀναθεματίζεσθαι.
Parallel canons
Ап.6208183IVВс.316Трул.21VIIВс.10Карф.16Двукр.11