Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV: The Fourth Ecumenical Council. The Council of Chalcedon.: Canon XXI
Clergymen and laymen bringing charges against bishops or clergymen are not to be received loosely and without examination, as accusers, but their own character shall first be investigated.
A cleric or layman making charges rashly against his bishop shall not be received.
Compare with this canon the VIth Canon of those credited to the First Synod at Constantinople, the second ecumenical.
This canon is found in the Corpus Juris Canonici, Gratian’s Decretum, Pars II., Causa II., Quæst. VII., canon xlix., in Isidore’s first version.