Library Ignatius of Antioch Epistles (Middle Recension)
Magnesians, Chapter 4: Some wickedly act independently of the bishop
It is fitting, then, not only to be called Christians, but to be so in reality: as some indeed give one the title of bishop, but do all things without him. Now such persons seem to me to be not possessed of a good conscience, seeing they are not stedfastly gathered together according to the commandment.
English translation in Ante-Nicene Fathers, Vol. I (eds. Alexander Roberts and James Donaldson; Buffalo: Christian Literature Publishing Co., 1885). Public domain. Digital text via New Advent Church Fathers. ANF prints the shorter Greek (middle) recension.