Ante-Nicene Fathers, Vol VIII:
The Decretals.: Part V

V.

That no one should have intercourse with those with whom the bishop has no intercourse, or receive those whom he rejects.

These things, then, we have set before you, most dearly beloved, in order that ye may unp. 621 derstand the power of your bishops, and give reverence to God in them, and love them as your own souls; and in order that ye may have no communication with those with whom they have none, and that ye may not receive those whom they have cast out.  For the judgment of a bishop is greatly to be feared, although he may bind one unjustly, which, however, he ought to guard against with the utmost care.