Правило 64
About the fact that a clergyman who fasts on Sunday or Saturday (except for Great Saturday) is ejected, and a layman is excommunicated.
If any cleric is found to fast on the Lord's Day or on Saturday (with the exception of only one Saturday), let him be deposed. If he is a layman, let him be excommunicated.
Greek original
Εἴ τις κληρικὸς εὑρεθῇ τὴν Κυριακὴν ἡμέραν νηστεύων, ἢ τὸ Σάββατον, (πλὴν τοῦ ἑνὸς μόνου), καθαιρείσθω· εἰ δὲ λαϊκός, ἀφοριζέσθω.
Parallel canons
Ап.5153IVВс.16Трул.1355Анкир.14Гангр.1821Лаод.294951