Canon 58
About the prohibition of laymen from giving communion to themselves or others (absence for 7 days).
Let no one from among the laity teach himself the Divine Mysteries when there is a bishop, or a presbyter, or a deacon. Anyone who dares to do anything like that, as one who acts contrary to what is prescribed, will be excommunicated for one week, thereby learning not to think more about himself than he ought to think (Rom. 12:3).
Greek original
Μηδεὶς τῶν ἐν λαϊκοῖς τεταγμένων ἑαυτῷ τῶν θείων μυστηρίων μεταδιδότω, παρόντος ἐπισκόπου, ἢ πρεσβυτέρoυ, ἢ διακόνου. Ὁ δέ τι τοιοῦτο τολμῶν, ὡς παρὰ τὰ διατεταγμένα ποιῶν, ἐπὶ ἑβδομάδα μίαν ἀφοριζέσθω, ἐντεῦθεν παιδαγωγούμενος, μὴ φρονεῖν παρ᾿ ὃ δεῖ φρονεῖν.
Parallel canons
IВс.1318