Правило 18
About anathema to those who fast on Sunday for the sake of imaginary asceticism.
If anyone fasts on Sunday for the sake of imaginary asceticism, let him be anathema.
Greek original
Εἴ τις διὰ νομιζομένην ἄσκησιν ἐν τῇ Κυριακῇ νηστεῦοι, ἀνάθεμα ἔστω.
Parallel canons
Ап.66IVВс.16Трул.55Анкир.14Лаод.294951